9 ms·

To catch a paedophile, you only need to look at their hands (2017)

34 points by NilsIRL 5y ago

h2odragon 5y ago
> he judge had to stop the trial for 90 minutes to ask her to explain the principles behind her analysis. Black explained her rationale, but conceded that she didn't have statistics showing the likelihood of the hands matching. "That research had never been done. I could say no more than everything matched, and we couldn't say it definitely wasn't him," she says. But we're really sure that vein patterns are unique, and c'mon! he's a pedophile! so really we can stretch the point and appeal to authority and say "the science is settled" even if it is actually more complicated; because this one case justifies it right? The implication there bugs me. Edit: Are vein patterns even static? Seems to me "varicose veins" etc show that they change over the scale of years, at least, right?
- kortex 5y ago
  > Are vein patterns even static? Nope. I had surgery one time to deal with a varicose vein of sorts. The key "engineering bug" was that the problem vein hits the collector vein at a 90° angle, instead of a "sliplane" (been playing too much mini motorways), causing congestion. The fix is to simply cut that connection. The body routes around it, increasing throughput through other networks. I don't think any entirely new routes were created, but I'm sure the size, geometry, and paths all changed. Worked well for about 15 years before the primary issues resumed. I'm yet to be convinced by the accuracy of this forensic method. Like, it would be one thing if they could actually provide stats, bayesian analysis, p/r curves, etc.
- User23 5y ago
  I don't know, but I've dealt with biometric authentication that looks at blood vessels in the hand.
- alpaca128 5y ago
  Reminds me of the cases which were "proven" with DNA evidence of the suspect's hairs, which often wasn't just a clear mismatch but sometimes not even human hair. But those revelations only came years or decades later.
  - Turing_Machine 5y ago
    Yes, or the one where the DNA "expert" testified that the odds were "millions to one" against a false match. Except that the (accused, but innocent) "perpetrator" was a member of (ethnic group), as was the actual perpetrator, and it turned out that a high percentage of members of (ethnic group) exhibited this allegedly rare DNA feature.
  - xyzzyz 5y ago
    It was actually worse than that. A lot of hair-based evidence wasn't even based on DNA, as there was no technology to sequence it at the time. It was from "experts" looking at hairs under microscope, comparing the "types" and "features", and seeing if they "match", according to their expert understanding. Suffice to say, their accuracy had zero nines at the front.
  - dukeofdoom 5y ago
    Reminds me of Doctor Tobin, ruling out fentynal, and saying that smoking isn't bad for you. Based on what science? My guess you can find an expert to say anything if it benefits them or their career. Lots of bullshit artists around.
- codefreakxff 5y ago
  Your question made me read the article. And it does seem to be lacking enough sample data. At one point she had 550 samples and that was called “substantial” in the article. Towards the end it had grown to 1000 samples. To your point the study is so small it does not attempt to answer the question in whether veins are static. There appears to be active research in this area in general. It does look like many companies and researchers are looking at ways to use vein patterns for bioinformatics https://biosmart-tech.com/tpost/megjc72d91-palm-vein-scanner-is-the-future-of-biome https://biosmart-tech.com/tpost/megjc72d91-palm-vein-scanner... https://res.mdpi.com/d_attachment/applsci/applsci-10-03192/article_deploy/applsci-10-03192.pdf https://res.mdpi.com/d_attachment/applsci/applsci-10-03192/a...
- sfink 5y ago
  I think it's reasonable to be suspicious of overzealous use of inadequate statistics, but the article quite clearly stated that Black is not making unwarranted claims about the accuracy. You're making a valid counterargument to a claim that was not made. I don't know how static vein patterns are, but in the particular case of varicose veins, my understanding is that they're existing veins that start to bulge outward. My guess would be that capillaries are pretty fungible, but the larger you get, the slower they'd change. For the best statistics, you'd probably want to incorporate the amount of time passing between two images, and model how much change is possible/reasonable. But there's plenty of signal to be had if you're careful to not overstate it.
  - BoppreH 5y ago
    > but the article quite clearly stated that Black is not making unwarranted claims about the accuracy I agree the she or the article are not making any claims. And she eventually got the study done. But by appearing in court as expert witness and presenting her analysis, she implicitly claimed that it's accurate enough to be taken as criminal evidence, and that was before doing the science. That's the dangerous part.
    - h2odragon 5y ago
      Thank you, that's a much better expression of what bugs me about this than I was able to come up with. One of the things, anyway.
- iforgotpassword 5y ago
  Well Yes, it was kinda the first step on new terrain. It was correctly not used as convicting evidence. But as it was filmed at night in the girls room with a hidden cam, it was a likely match, and that's probably what motivated her to keep doing research in that direction. Later cases described in the article were using more features than just vein patterns. Plus evidence unrelated to hands. While a sample of 1000 to compare against is certainly small, it's in the ballpark where it's valid supporting evidence. And if you want to make it better, maybe just contact Black and ask if/how you could submit your own sample?
- radu_floricica 5y ago
  I don't think the problem is with the number of samples. You're not trying to identify the culprit (automatically) among many potential suspects. You're doing what is basic scientific research: you're using all the data you have to try to _disprove_ that he's that guy - which you can do with near 100% certainty. Any missing feature can clear him. After a certain amount of effort you give up. Which means the trust you have in the team is a lot more important than the size of the dataset. I don't know how checks and balances would look here. Maybe make available each analysis to the defendant and let him/his team check it out? Like another commenter said in this thread, some people were convicted on DNA evidence of a hair that wasn't even human. A larger sample won't fix that.
  - LorenPechtel 5y ago
    The size of the dataset sets the maximum odds of a false positive. We are seeing false positive problems with DNA and the FBI won't cooperate into investigating. (The problem comes from relatives--while two random people are astronomically unlikely to false positive close relatives are likely to have many matches anyway, the odds of a false positive are merely low, not astronomical.)
- boublepop 5y ago
  > Are vein patterns even static? What does that matter? Imagine some other characteristic that definitely changes over time lets say your clothing. The case in question had an expert saying: “Yes, the person recorded in the video is wearing the exact same clothes that we know the father was wearing the night of the incident, and that he is also wearing to court today. Now mind you, we dont know the exact statistical lilelihood that someone else would wear the exact same pants, shirt, tie, shoes and hat.” Your attempted counter argument is “yes ok, that is definitely the same clothes that the perpetrator was wearing and that the defendant wore that night and today, but he could change his clothes tomorrow, so…”
  - treesprite82 5y ago
    Assume we're starting with a 1% prior of some person being the the perpetrator of a crime. Consider some completely static characteristic. If the suspect is the perpetrator then there's an 100% chance they still have this characteristic, whereas if the suspect is innocent then there's a 10% chance they have this characteristic just by coincidence. Therefore if the suspect turns out to have this characteristic, you should update your prior to (1*0.01)/0.1 = 10%. Compare to some dynamic characteristic. If the suspect is the perpetrator then there's an 20% chance they still have this characteristic, whereas if the suspect is innocent then there's a 10% chance they have this characteristic just by coincidence. Therefore if the suspect turns out to have this characteristic, you should update your prior to (0.2*0.01)/0.1 = 2%. At the extreme, a completely dynamic characteristic. If the suspect is the perpetrator then there's a 10% chance they still have this characteristic, whereas if the suspect is innocent then there's a 10% chance they have this characteristic just by coincidence. Clearly in this case you shouldn't update your prior at all.
- Ancapistani 5y ago
  I think I agree with you in a broader sense, but I don’t understand why this case in particular seems to be an issue. > "That research had never been done. I could say no more than everything matched, and we couldn't say it definitely wasn't him” This seems to be exactly correct. It explicits says that it was not possible given the information at time to confidently identify someone from a photo, but that there was enough information to positively rule out identification in some cases - and that that wasn’t the case here.
roenxi 5y ago
> Black explained her rationale, but conceded that she didn't have statistics showing the likelihood of the hands matching. It looks like an open & shut case to me, but this sort of thing should be grounds for concern in a court case. Evidence that can be statistically quantified should be. Especially novel identification techniques. I'm glad that more research went in to the technique before the convictions started to happen.
- nyolfen 5y ago
  otoh 'more research' seems to be a database of 1000 individuals compiled and analyzed by an individual. this appears to be founded on ad hoc visual inspections without theoretical underpinnings, and seems like a scientific cargo cult like many other forensic science methods.
  - ttyprintk 5y ago
    Agreed. Before admitting it in court, it should reach a confidence of disproving someone’s identity before being believed to prove* another identity. Edit: (*) beyond a reasonable doubt, as expressed in the law.
    - mcphage 5y ago
      > Before admitting it in court, it should reach a confidence of disproving someone’s identity before being believed to prove* another identity. Which is exactly how it was used in the case in question—Black said it couldn’t prove the identity of the attacker, but was enough to show they couldn’t exclude the girl’s father.
- LorenPechtel 5y ago
  I don't think her case needed more research. She said her father was molesting her. She set a webcam, somebody was certainly molesting her. Why would one think she was identifying the wrong person?
TrackerFF 5y ago
Sounds like pedophiles will start to wear gloves, or similar ways to obfuscate hands etc., now that they know what people are watching for.
- sfink 5y ago
  This was specifically addressed in the article. (I'm not saying that Black's answer is necessarily 100% correct or complete, but she addressed it.)
- lemonberry 5y ago
  A better strategy is to get help and not be a pedophile.
  - lilboiluvr69 5y ago
    There is no treatment (that I know of) to convert someone's sexual orientation from one that is exclusive to children to one that does not include children. A pedophile or minor attracted person does not however necessarily need to become a child molester. Not that this article makes a distinction, or anyone else... I sure do appreciate do the oft repeated quip of 'get help', as if its my responsibility for being this way and if I just enroll in the appropriate treatment (and what decent person wouldn't?) I could get fixed and become a normal productive member of society like everyone else. But it's probably easier to dehumanize me if you think that I'm such an evil person I willingly choose rather to remain exclusively attracted to a group of people I can never have a healthy fulfilling relationship with, that I'd choose perversion over my own happiness. Source: Am a pedophile who doesn't rape children or look at CP.
    - sterlind 5y ago
      You're right that conversion therapy doesn't work, but there's at least medication to kill your sex drive so you're not tortured by the temptation. GnRH agonists will null out your sex hormones. And therapy can help you deal with the temptation -- even though it's not a cure, there's techniques like CBT and ACT and other strategies for getting your mind off it. And like it or not, it is your responsibility to get that sort of therapy and get medication. I do find your username exceedingly tasteless, though.
polar 5y ago
[2017] Ongoing research: * https://whatworks.college.police.uk/Research/Research-Map/Pages/ResearchProject.aspx?projectid=797 https://whatworks.college.police.uk/Research/Research-Map/Pa... * https://www.lancaster.ac.uk/security-lancaster/research/h-unique/ https://www.lancaster.ac.uk/security-lancaster/research/h-un...
orwin 5y ago
This title is horrible. The interesting thing here is that it might be possible to identify people thank to their hands (as they seems to be unique enough). But man, reading this was upsetting. While this might appear light for some, it is much details for me (i understand trigger warnings now :/)
neurotology 5y ago
Don't they mean, "to catch a molester?" It should be at least theoretically possible for someone to be a paedophile and not a molester, the same way one can be a heterosexual without being a rapist.
- voxl 5y ago
  No, pedophiles are evil even if they never assault or harass anyone in their entire life. /s
belltaco 5y ago
>If you're wondering why no one is investing billions to create million-strong data sets, Black says it's because there's no money for research into catching child abusers. Maybe a certain fruit company that's sitting on 200+ billion in cash can help?
- ttyprintk 5y ago
  What do you think of scrapping the perceptual hash and reorganizing those resources for an initial effort of catching ONE perp. Just one, a case to see what it takes to get the evidence together for a conviction of the actor, not a “ring” of file swappers. I’d find that much more satisfying. Maybe every video can be scrutinized. What about the bedding or linoleum on the floor has appeared in other videos? Maybe the carpet is only prominently available in certain countries.
deleted 5y ago
[deleted]
1024core 5y ago
> A key photo - later known as "the Hogmanay image" - showed one of the two ringleaders, Neil Strachan, 41, attempting to rape an 18-month-old boy whom he was babysitting on New Year's Eve.... In October 2009, Strachan was sentenced to life imprisonment with a minimum term of 16 years, cut on appeal to nine years. Just 9 fucking years for abusing an 18-month old child?!?!?? What is wrong with the authorities there?
vagrantJin 5y ago
It is hilarious how much we still treat pedophilia like 18th century atheists. "Look! Heathens!, lock them up" mentality that gets us absolutely nowhere. The article is good and all but I can't see how it's an improvement from DNA profiling - its just a step above left handed voodoo. Which is odd, since we are so concerned about mental health issues it seems the pyschological aspect of pedophilia is hardly explored. The notion of bury them beneath the prison whilst we put our heads in the sand should be of serious concern.
- jhanschoo 5y ago
  The article uses the word pedophile, but it's clear that it's only discussing child sexual abuse.
- Grieving 5y ago
  There are few other crimes so heinous and with such a high recidivism rate as sexual abuse of children. Attempting to reforming such people appears to be a fool's errand (and that's leaving aside that retributive justice is a real and necessary component of a serious society). I know the usual response is that not all pedophiles are going to actually carry out their fantasies, but really we have no evidence that "non-offending MAPs" or "virtuous pedophiles" (or whatever they call themselves) are a real or significant phenomenon; plenty of those who have claimed these titles have been exposed as abusers.
lilboiluvr69 5y ago
Child pornography will always exist as long as there is a demand for it without any available substitutions. And there will always be a demand for it as long as pedophiles exist. And pedophiles have always existed and as far as we know always will exist and are probably a lot larger part of the population than most people expect. Like the war on drugs, this is a battle that is never going to end. I wish some government agency, maybe NCMEC or someone else, would realize this and try actually catering to pedophiles as citizens of their country rather than pretending they are vermin that can be stomped out. Imagine if a government put their vast resources into creating artificial child pornography so that people who want to look at child pornography (or perhaps aren't pedophiles but are just curious) have an outlet that doesn't actually involve children. There are a million ways to do this. You could train a GAN on actual CP images that produce new original images without any actual victims, or maybe with enough talented researchers create one that never involved children to begin with. You could pay some very talented CGI companies to create realistic child pornography, maybe with the help with actors that already look underaged but are not. Or maybe even just commission some shotacon artists or cub furs artists off Inkbunny (although the community is already doing this.) "Hey, we realize that you're sexually attracted to children and like all people have sexual desires that need to be fulfilled in order to be happy. We know you're not a bad person and we're sorry we can't give you real children to have sex with, but here are some links to artificial child pornography we've made so that you can be less sexually frustrated without breaking the law." I really don't understand why, if the goal is to prevent the sexual exploitation of children, any government hasn't tried making photo-realistic synthetic child pornography. It seems like such an obvious solution that would actually make gains in reducing the consumption of child pornography. I suspect most pedophiles who do consume child pornography would stick with a realistic ethically-made artificial alternative, if only to avoid possible prosecution.
- anchpop 5y ago
  Even if we entertain the possibility that one could create fully-ethically-produced pornography that pedophiles would like (maybe using adult actors that look much younger than they are, or something), there are still some problems. It’s well known that some people develop fetishes, where they can only orgasm by experiencing their particular kinks. Probably if they had never seen porn that contained these kinks, they wouldn’t have developed into a fetish. So you could imagine someone who’s a half-pedophile, attracted to adults as well as kids, becoming a full pedophile after too much exposure to child pornography. That would be a pretty negative outcome. Politically though, anything that improves the lives of pedophiles is a complete nonstarter regardless of how many children it saves from being raped. Because if you propose something that improves the lives of pedophiles, everyone will say “hmm, pretty suspicious that this is your pet project, how do we know you’re not a pedophile?”. So the whole discussion is kind of moot.
treesprite82 5y ago
> Black compared the left thumb in the picture with the Hogmanay image and found matching details, including an unusually shaped lunule, the white area at the base of the nail. "This time, I was able to go back to my database and put statistics to the data." > Once they have established the offender's features, they study images of the suspect, trying to establish a match. The method as described by the article seems precarious. There's a lot of room for human bias to sneak in when there's prior expectation of which thumbs should match. Easy to be lenient when matching features to the suspect's thumb, and strict when matching features to the dataset which you already know shouldn't match and would undermine your method if you found matches. Deciding the features by comparing the suspect to the offender also introduces pitfalls. If randomly selected hands have 5 out of 20 matching features, then in most cases you'll be able to claim that a completely random hand matches the offender's hand in a way that 0% of images in the 500-image database do. An improvement might be to have one person indiscriminately categorize features of the suspect's hand, and a separate person indiscriminately categorize features of the hand in the video. Neither person should see both images - especially not when deciding which features are relevant. > The Oketch case presented her with two technical problems. First, he was black, "and all the people we had looked at previously had been white. This has a lot of the smells of evidence analysis techniques that we find out in 20 years were ill-founded and lead to a bunch of false imprisonments. > A suspect can be excluded with 100 per cent certainty, but a match can only carry a grade of "strong support" that the suspect and the offender are the same person. This equates to between a 1-in-1,000 to 1-in-10,000 chance that it could be someone else. I worry that courts aren't properly equipped to understand that false positive rates aren't "the chance that it could be someone else". As an extreme scenario, imagine it's 2050 and you're suspected of a crime based solely on a match from a comprehensive global facial recognition system (~10 billion faces). If the system has a has a 1-in-1,000,000,000 false positive rate, then that still means there's a 90% chance you're innocent (if given no other information).
karmakaze 5y ago
The comments here seem to suggest an unjustified process of unvalidated 'expert' testimony. What I picked up on the article was: > In the end, the match appeared strong. When presented with Black's report, Oketch changed his plea from not guilty to guilty; he got 15 years. That plea change was important, Black says. It meant money that would otherwise have been spent on trials was saved. It also meant the child was spared from having to give evidence in court.
karmakaze 5y ago
> "Can't our phones recognise parts of a body and stop the image being taken?" she asks. "That's the challenge I want companies such as Apple to take up, to stop technology being a mechanism by which our children's innocence is being stolen. Because, you know, the statistics say that one in six people have had unwanted sexual attention as a child. One in six. I cannot think of a crime that is more important. Can you?" It's strange to see this case dug up from 2017 asking for Apple to make tech to stop these crimes. Technology isn't moral and doesn't discriminate in application. As important as this cause is, I would look in many, many places before coming to a conclusion that no one can have privacy and that scanning everyone's devices 'just in case' is ok. That future, I imagine is worse.
Ancapistani 5y ago
This stood out to me: > On average, men have 50 per cent more scars than women, but right-handed men are more likely to scar their left hands, while right-handed women tend to scar their right - no one knows why. I asked my wife, and the best hypotheses that we could come up with together are: * men are more likely to use tools, and to use them aggressively. Tool use is typically done with the dominant hand, while injury through tool use would typically be to the non-dominant hand * women are more likely to perform tasks that require fine dexterity, which would often preclude the use of tools
xyzzy21 5y ago
This sounds far too much like phrenology and tendencies to be criminals. Default position: it's probably bull shit!
tailius 5y ago
The jury acquitted because "the girl didn't seem upset enough." How upset does one need to be throughout the course of an entire trial? Are they implying she liked it , welcomed it, or made it up because she wasn't sobbing constantly? What possible motivation would she have to drag herself and her family through a jury trial if it were untrue?

34 points by NilsIRL 5y ago

> he judge had to stop the trial for 90 minutes to ask her to explain the principles behind her analysis. Black explained her rationale, but conceded that she didn't have statistics showing the likelihood of the hands matching. "That research had never been done. I could say no more than everything matched, and we couldn't say it definitely wasn't him," she says. But we're really sure that vein patterns are unique, and c'mon! he's a pedophile! so really we can stretch the point and appeal to authority and say "the science is settled" even if it is actually more complicated; because this one case justifies it right? The implication there bugs me. Edit: Are vein patterns even static? Seems to me "varicose veins" etc show that they change over the scale of years, at least, right?

kortex 5y ago
> Are vein patterns even static? Nope. I had surgery one time to deal with a varicose vein of sorts. The key "engineering bug" was that the problem vein hits the collector vein at a 90° angle, instead of a "sliplane" (been playing too much mini motorways), causing congestion. The fix is to simply cut that connection. The body routes around it, increasing throughput through other networks. I don't think any entirely new routes were created, but I'm sure the size, geometry, and paths all changed. Worked well for about 15 years before the primary issues resumed. I'm yet to be convinced by the accuracy of this forensic method. Like, it would be one thing if they could actually provide stats, bayesian analysis, p/r curves, etc.
User23 5y ago
I don't know, but I've dealt with biometric authentication that looks at blood vessels in the hand.
alpaca128 5y ago
Reminds me of the cases which were "proven" with DNA evidence of the suspect's hairs, which often wasn't just a clear mismatch but sometimes not even human hair. But those revelations only came years or decades later.
- Turing_Machine 5y ago
  Yes, or the one where the DNA "expert" testified that the odds were "millions to one" against a false match. Except that the (accused, but innocent) "perpetrator" was a member of (ethnic group), as was the actual perpetrator, and it turned out that a high percentage of members of (ethnic group) exhibited this allegedly rare DNA feature.
- xyzzyz 5y ago
  It was actually worse than that. A lot of hair-based evidence wasn't even based on DNA, as there was no technology to sequence it at the time. It was from "experts" looking at hairs under microscope, comparing the "types" and "features", and seeing if they "match", according to their expert understanding. Suffice to say, their accuracy had zero nines at the front.
- dukeofdoom 5y ago
  Reminds me of Doctor Tobin, ruling out fentynal, and saying that smoking isn't bad for you. Based on what science? My guess you can find an expert to say anything if it benefits them or their career. Lots of bullshit artists around.
codefreakxff 5y ago
Your question made me read the article. And it does seem to be lacking enough sample data. At one point she had 550 samples and that was called “substantial” in the article. Towards the end it had grown to 1000 samples. To your point the study is so small it does not attempt to answer the question in whether veins are static. There appears to be active research in this area in general. It does look like many companies and researchers are looking at ways to use vein patterns for bioinformatics https://biosmart-tech.com/tpost/megjc72d91-palm-vein-scanner-is-the-future-of-biome https://biosmart-tech.com/tpost/megjc72d91-palm-vein-scanner... https://res.mdpi.com/d_attachment/applsci/applsci-10-03192/article_deploy/applsci-10-03192.pdf https://res.mdpi.com/d_attachment/applsci/applsci-10-03192/a...
sfink 5y ago
I think it's reasonable to be suspicious of overzealous use of inadequate statistics, but the article quite clearly stated that Black is not making unwarranted claims about the accuracy. You're making a valid counterargument to a claim that was not made. I don't know how static vein patterns are, but in the particular case of varicose veins, my understanding is that they're existing veins that start to bulge outward. My guess would be that capillaries are pretty fungible, but the larger you get, the slower they'd change. For the best statistics, you'd probably want to incorporate the amount of time passing between two images, and model how much change is possible/reasonable. But there's plenty of signal to be had if you're careful to not overstate it.
- BoppreH 5y ago
  > but the article quite clearly stated that Black is not making unwarranted claims about the accuracy I agree the she or the article are not making any claims. And she eventually got the study done. But by appearing in court as expert witness and presenting her analysis, she implicitly claimed that it's accurate enough to be taken as criminal evidence, and that was before doing the science. That's the dangerous part.
  - h2odragon 5y ago
    Thank you, that's a much better expression of what bugs me about this than I was able to come up with. One of the things, anyway.
iforgotpassword 5y ago
Well Yes, it was kinda the first step on new terrain. It was correctly not used as convicting evidence. But as it was filmed at night in the girls room with a hidden cam, it was a likely match, and that's probably what motivated her to keep doing research in that direction. Later cases described in the article were using more features than just vein patterns. Plus evidence unrelated to hands. While a sample of 1000 to compare against is certainly small, it's in the ballpark where it's valid supporting evidence. And if you want to make it better, maybe just contact Black and ask if/how you could submit your own sample?
radu_floricica 5y ago
I don't think the problem is with the number of samples. You're not trying to identify the culprit (automatically) among many potential suspects. You're doing what is basic scientific research: you're using all the data you have to try to _disprove_ that he's that guy - which you can do with near 100% certainty. Any missing feature can clear him. After a certain amount of effort you give up. Which means the trust you have in the team is a lot more important than the size of the dataset. I don't know how checks and balances would look here. Maybe make available each analysis to the defendant and let him/his team check it out? Like another commenter said in this thread, some people were convicted on DNA evidence of a hair that wasn't even human. A larger sample won't fix that.
- LorenPechtel 5y ago
  The size of the dataset sets the maximum odds of a false positive. We are seeing false positive problems with DNA and the FBI won't cooperate into investigating. (The problem comes from relatives--while two random people are astronomically unlikely to false positive close relatives are likely to have many matches anyway, the odds of a false positive are merely low, not astronomical.)
boublepop 5y ago
> Are vein patterns even static? What does that matter? Imagine some other characteristic that definitely changes over time lets say your clothing. The case in question had an expert saying: “Yes, the person recorded in the video is wearing the exact same clothes that we know the father was wearing the night of the incident, and that he is also wearing to court today. Now mind you, we dont know the exact statistical lilelihood that someone else would wear the exact same pants, shirt, tie, shoes and hat.” Your attempted counter argument is “yes ok, that is definitely the same clothes that the perpetrator was wearing and that the defendant wore that night and today, but he could change his clothes tomorrow, so…”
- treesprite82 5y ago
  Assume we're starting with a 1% prior of some person being the the perpetrator of a crime. Consider some completely static characteristic. If the suspect is the perpetrator then there's an 100% chance they still have this characteristic, whereas if the suspect is innocent then there's a 10% chance they have this characteristic just by coincidence. Therefore if the suspect turns out to have this characteristic, you should update your prior to (1*0.01)/0.1 = 10%. Compare to some dynamic characteristic. If the suspect is the perpetrator then there's an 20% chance they still have this characteristic, whereas if the suspect is innocent then there's a 10% chance they have this characteristic just by coincidence. Therefore if the suspect turns out to have this characteristic, you should update your prior to (0.2*0.01)/0.1 = 2%. At the extreme, a completely dynamic characteristic. If the suspect is the perpetrator then there's a 10% chance they still have this characteristic, whereas if the suspect is innocent then there's a 10% chance they have this characteristic just by coincidence. Clearly in this case you shouldn't update your prior at all.
Ancapistani 5y ago
I think I agree with you in a broader sense, but I don’t understand why this case in particular seems to be an issue. > "That research had never been done. I could say no more than everything matched, and we couldn't say it definitely wasn't him” This seems to be exactly correct. It explicits says that it was not possible given the information at time to confidently identify someone from a photo, but that there was enough information to positively rule out identification in some cases - and that that wasn’t the case here.

roenxi 5y ago

> Black explained her rationale, but conceded that she didn't have statistics showing the likelihood of the hands matching. It looks like an open & shut case to me, but this sort of thing should be grounds for concern in a court case. Evidence that can be statistically quantified should be. Especially novel identification techniques. I'm glad that more research went in to the technique before the convictions started to happen.

nyolfen 5y ago
otoh 'more research' seems to be a database of 1000 individuals compiled and analyzed by an individual. this appears to be founded on ad hoc visual inspections without theoretical underpinnings, and seems like a scientific cargo cult like many other forensic science methods.
- ttyprintk 5y ago
  Agreed. Before admitting it in court, it should reach a confidence of disproving someone’s identity before being believed to prove* another identity. Edit: (*) beyond a reasonable doubt, as expressed in the law.
  - mcphage 5y ago
    > Before admitting it in court, it should reach a confidence of disproving someone’s identity before being believed to prove* another identity. Which is exactly how it was used in the case in question—Black said it couldn’t prove the identity of the attacker, but was enough to show they couldn’t exclude the girl’s father.
LorenPechtel 5y ago
I don't think her case needed more research. She said her father was molesting her. She set a webcam, somebody was certainly molesting her. Why would one think she was identifying the wrong person?

TrackerFF 5y ago

Sounds like pedophiles will start to wear gloves, or similar ways to obfuscate hands etc., now that they know what people are watching for.

sfink 5y ago
This was specifically addressed in the article. (I'm not saying that Black's answer is necessarily 100% correct or complete, but she addressed it.)
lemonberry 5y ago
A better strategy is to get help and not be a pedophile.
- lilboiluvr69 5y ago
  There is no treatment (that I know of) to convert someone's sexual orientation from one that is exclusive to children to one that does not include children. A pedophile or minor attracted person does not however necessarily need to become a child molester. Not that this article makes a distinction, or anyone else... I sure do appreciate do the oft repeated quip of 'get help', as if its my responsibility for being this way and if I just enroll in the appropriate treatment (and what decent person wouldn't?) I could get fixed and become a normal productive member of society like everyone else. But it's probably easier to dehumanize me if you think that I'm such an evil person I willingly choose rather to remain exclusively attracted to a group of people I can never have a healthy fulfilling relationship with, that I'd choose perversion over my own happiness. Source: Am a pedophile who doesn't rape children or look at CP.
  - sterlind 5y ago
    You're right that conversion therapy doesn't work, but there's at least medication to kill your sex drive so you're not tortured by the temptation. GnRH agonists will null out your sex hormones. And therapy can help you deal with the temptation -- even though it's not a cure, there's techniques like CBT and ACT and other strategies for getting your mind off it. And like it or not, it is your responsibility to get that sort of therapy and get medication. I do find your username exceedingly tasteless, though.

polar 5y ago

[2017] Ongoing research: * https://whatworks.college.police.uk/Research/Research-Map/Pages/ResearchProject.aspx?projectid=797 https://whatworks.college.police.uk/Research/Research-Map/Pa... * https://www.lancaster.ac.uk/security-lancaster/research/h-unique/ https://www.lancaster.ac.uk/security-lancaster/research/h-un...

orwin 5y ago

This title is horrible. The interesting thing here is that it might be possible to identify people thank to their hands (as they seems to be unique enough). But man, reading this was upsetting. While this might appear light for some, it is much details for me (i understand trigger warnings now :/)

neurotology 5y ago

Don't they mean, "to catch a molester?" It should be at least theoretically possible for someone to be a paedophile and not a molester, the same way one can be a heterosexual without being a rapist.

voxl 5y ago
No, pedophiles are evil even if they never assault or harass anyone in their entire life. /s

belltaco 5y ago

>If you're wondering why no one is investing billions to create million-strong data sets, Black says it's because there's no money for research into catching child abusers. Maybe a certain fruit company that's sitting on 200+ billion in cash can help?

ttyprintk 5y ago
What do you think of scrapping the perceptual hash and reorganizing those resources for an initial effort of catching ONE perp. Just one, a case to see what it takes to get the evidence together for a conviction of the actor, not a “ring” of file swappers. I’d find that much more satisfying. Maybe every video can be scrutinized. What about the bedding or linoleum on the floor has appeared in other videos? Maybe the carpet is only prominently available in certain countries.

deleted 5y ago

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1024core 5y ago

> A key photo - later known as "the Hogmanay image" - showed one of the two ringleaders, Neil Strachan, 41, attempting to rape an 18-month-old boy whom he was babysitting on New Year's Eve.... In October 2009, Strachan was sentenced to life imprisonment with a minimum term of 16 years, cut on appeal to nine years. Just 9 fucking years for abusing an 18-month old child?!?!?? What is wrong with the authorities there?

vagrantJin 5y ago

It is hilarious how much we still treat pedophilia like 18th century atheists. "Look! Heathens!, lock them up" mentality that gets us absolutely nowhere. The article is good and all but I can't see how it's an improvement from DNA profiling - its just a step above left handed voodoo. Which is odd, since we are so concerned about mental health issues it seems the pyschological aspect of pedophilia is hardly explored. The notion of bury them beneath the prison whilst we put our heads in the sand should be of serious concern.

jhanschoo 5y ago
The article uses the word pedophile, but it's clear that it's only discussing child sexual abuse.
Grieving 5y ago
There are few other crimes so heinous and with such a high recidivism rate as sexual abuse of children. Attempting to reforming such people appears to be a fool's errand (and that's leaving aside that retributive justice is a real and necessary component of a serious society). I know the usual response is that not all pedophiles are going to actually carry out their fantasies, but really we have no evidence that "non-offending MAPs" or "virtuous pedophiles" (or whatever they call themselves) are a real or significant phenomenon; plenty of those who have claimed these titles have been exposed as abusers.

lilboiluvr69 5y ago

Child pornography will always exist as long as there is a demand for it without any available substitutions. And there will always be a demand for it as long as pedophiles exist. And pedophiles have always existed and as far as we know always will exist and are probably a lot larger part of the population than most people expect. Like the war on drugs, this is a battle that is never going to end. I wish some government agency, maybe NCMEC or someone else, would realize this and try actually catering to pedophiles as citizens of their country rather than pretending they are vermin that can be stomped out. Imagine if a government put their vast resources into creating artificial child pornography so that people who want to look at child pornography (or perhaps aren't pedophiles but are just curious) have an outlet that doesn't actually involve children. There are a million ways to do this. You could train a GAN on actual CP images that produce new original images without any actual victims, or maybe with enough talented researchers create one that never involved children to begin with. You could pay some very talented CGI companies to create realistic child pornography, maybe with the help with actors that already look underaged but are not. Or maybe even just commission some shotacon artists or cub furs artists off Inkbunny (although the community is already doing this.) "Hey, we realize that you're sexually attracted to children and like all people have sexual desires that need to be fulfilled in order to be happy. We know you're not a bad person and we're sorry we can't give you real children to have sex with, but here are some links to artificial child pornography we've made so that you can be less sexually frustrated without breaking the law." I really don't understand why, if the goal is to prevent the sexual exploitation of children, any government hasn't tried making photo-realistic synthetic child pornography. It seems like such an obvious solution that would actually make gains in reducing the consumption of child pornography. I suspect most pedophiles who do consume child pornography would stick with a realistic ethically-made artificial alternative, if only to avoid possible prosecution.

anchpop 5y ago
Even if we entertain the possibility that one could create fully-ethically-produced pornography that pedophiles would like (maybe using adult actors that look much younger than they are, or something), there are still some problems. It’s well known that some people develop fetishes, where they can only orgasm by experiencing their particular kinks. Probably if they had never seen porn that contained these kinks, they wouldn’t have developed into a fetish. So you could imagine someone who’s a half-pedophile, attracted to adults as well as kids, becoming a full pedophile after too much exposure to child pornography. That would be a pretty negative outcome. Politically though, anything that improves the lives of pedophiles is a complete nonstarter regardless of how many children it saves from being raped. Because if you propose something that improves the lives of pedophiles, everyone will say “hmm, pretty suspicious that this is your pet project, how do we know you’re not a pedophile?”. So the whole discussion is kind of moot.

treesprite82 5y ago

> Black compared the left thumb in the picture with the Hogmanay image and found matching details, including an unusually shaped lunule, the white area at the base of the nail. "This time, I was able to go back to my database and put statistics to the data." > Once they have established the offender's features, they study images of the suspect, trying to establish a match. The method as described by the article seems precarious. There's a lot of room for human bias to sneak in when there's prior expectation of which thumbs should match. Easy to be lenient when matching features to the suspect's thumb, and strict when matching features to the dataset which you already know shouldn't match and would undermine your method if you found matches. Deciding the features by comparing the suspect to the offender also introduces pitfalls. If randomly selected hands have 5 out of 20 matching features, then in most cases you'll be able to claim that a completely random hand matches the offender's hand in a way that 0% of images in the 500-image database do. An improvement might be to have one person indiscriminately categorize features of the suspect's hand, and a separate person indiscriminately categorize features of the hand in the video. Neither person should see both images - especially not when deciding which features are relevant. > The Oketch case presented her with two technical problems. First, he was black, "and all the people we had looked at previously had been white. This has a lot of the smells of evidence analysis techniques that we find out in 20 years were ill-founded and lead to a bunch of false imprisonments. > A suspect can be excluded with 100 per cent certainty, but a match can only carry a grade of "strong support" that the suspect and the offender are the same person. This equates to between a 1-in-1,000 to 1-in-10,000 chance that it could be someone else. I worry that courts aren't properly equipped to understand that false positive rates aren't "the chance that it could be someone else". As an extreme scenario, imagine it's 2050 and you're suspected of a crime based solely on a match from a comprehensive global facial recognition system (~10 billion faces). If the system has a has a 1-in-1,000,000,000 false positive rate, then that still means there's a 90% chance you're innocent (if given no other information).

karmakaze 5y ago

The comments here seem to suggest an unjustified process of unvalidated 'expert' testimony. What I picked up on the article was: > In the end, the match appeared strong. When presented with Black's report, Oketch changed his plea from not guilty to guilty; he got 15 years. That plea change was important, Black says. It meant money that would otherwise have been spent on trials was saved. It also meant the child was spared from having to give evidence in court.

karmakaze 5y ago

> "Can't our phones recognise parts of a body and stop the image being taken?" she asks. "That's the challenge I want companies such as Apple to take up, to stop technology being a mechanism by which our children's innocence is being stolen. Because, you know, the statistics say that one in six people have had unwanted sexual attention as a child. One in six. I cannot think of a crime that is more important. Can you?" It's strange to see this case dug up from 2017 asking for Apple to make tech to stop these crimes. Technology isn't moral and doesn't discriminate in application. As important as this cause is, I would look in many, many places before coming to a conclusion that no one can have privacy and that scanning everyone's devices 'just in case' is ok. That future, I imagine is worse.

Ancapistani 5y ago

This stood out to me: > On average, men have 50 per cent more scars than women, but right-handed men are more likely to scar their left hands, while right-handed women tend to scar their right - no one knows why. I asked my wife, and the best hypotheses that we could come up with together are: * men are more likely to use tools, and to use them aggressively. Tool use is typically done with the dominant hand, while injury through tool use would typically be to the non-dominant hand * women are more likely to perform tasks that require fine dexterity, which would often preclude the use of tools

xyzzy21 5y ago

This sounds far too much like phrenology and tendencies to be criminals. Default position: it's probably bull shit!

tailius 5y ago

The jury acquitted because "the girl didn't seem upset enough." How upset does one need to be throughout the course of an entire trial? Are they implying she liked it , welcomed it, or made it up because she wasn't sobbing constantly? What possible motivation would she have to drag herself and her family through a jury trial if it were untrue?