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I think if law enforcement uses these DNA databases then their entire department should be required to submit each officer’s DNA and that of their immediate fam

I think if law enforcement uses these DNA databases then their entire department should be required to submit each officer’s DNA and that of their immediate family members too. If prosecutors or defending attorneys want to use these databases, then the same should go for them. If a judge admits the use of DNA evidence for a case, then the same goes for them. Politicians by virtue passing these laws should get that same treatment. Maybe the way to solve this issue is for law enforcement to be required to mail a letter to everyone who is in the database that they are a suspect in whatever crime being investigated each time law enforcement executed or delegates the execution of a search query. I mean that is how search works: you search everything or you compute hash functions on everything to avoid searching everything, but you’ve effectively tested whether or not everyone in the database is the suspect. On a slightly different topic, how well are these DNA databases secured and maintained? A person’s DNA might not change, but the corresponding entry in the DNA database is subject to theft, manipulation, and data corruption. What’s stopping the presumption of innocence until proven guilty becoming the presumption of innocence until the DNA database reports a match? Arguably, people should treat DNA databases with the same level of suspicion and concern as some view electronic voting: absolutely vulnerable and absolutely abusable until repeatedly proven to be not sufficiently many times.

foota 7y ago
I don't think these are typically used (or could be used) to convict someone, I think it's mostly used to guide investigations.
- astura 7y ago
  This is correct, it's used to find suspects, not to convict anyone.
  - geggam 7y ago
    AKA fishing
    - gbrown 7y ago
      If done right, spear fishing. I'm a privacy guy, but the science really is there to use DNA to narrow a list of suspects. You can't say the same for much of forensic science, or for that matter mass surveillance technologies.
      - tareqak 7y ago
        However, the list of suspects can still lack the actual criminal(s), but still contain an innocent with poor, but true alibi.
        tbyehl 7y ago
        Here's an actual case of an innocent person who faced charges and a high probability of losing their freedom due to DNA transference: https://www.wired.com/story/dna-transfer-framed-murder/ https://www.wired.com/story/dna-transfer-framed-murder/ The take-away is that shed skin cells containing DNA can migrate and a DNA match from that type of evidence shouldn't be relied on as proof of anything. To my view, the combination of DNA transference, advancing DNA collection / analysis techniques, the mere existence of DNA databases, and familial searches are absolutely terrifying.
        gbrown 7y ago
        Good counterpoint, definitely an issue. When the police find macroscopic quantities of bodily fluids, however, it would seem to be madness not to use the evidence.
        tbyehl 7y ago
        Absolutely. I do question if society is better off catching a few more criminals through these databases and familial matching vs the potential for innocents to be imprisoned based on nothing more than a DNA match against skin cells. I'm also not too fond of the idea of my relatives' DNA being used to draw suspicion to another relative just because someone's DNA wound up in a database. To me it's just another one of those things (ALPRs, all the compilations of "it's just metadata") that erode our privacy and give the state a great deal of power for relatively little benefit to the people. All crimes don't get solved, all criminals don't get caught, and in a society where everyone's a law-breaker because there are too many laws to know them all and so many of them are dumb, that's how things should be.
- monocasa 7y ago
  Why wouldn't they be allowed to be used? Anything that guides an investigation is supposed to be admissable evidence or else you get into fruit of the poisonous tree territory, which is illegal. Not saying it wouldn't happen still, but they wouldn't be talking about using it in that case. It'd be like with stingrays where they publicly claim that they got a tip from a confidential informant and drop cases on anyone who gets close to the truth so the never actually get a judge to tell them they can't do it.
  - brownbat 7y ago
    > Anything that guides an investigation is supposed to be admissable evidence or else you get into fruit of the poisonous tree territory, which is illegal. Slight correction here. The FPT doctrine makes it so most[0] evidence obtained illegally cannot be admitted. It doesn't work in reverse, it does not imply that all inadmissible evidence is illegal. For example, the first half of many investigations is full of inadmissible hearsay, before you narrow in on what happened and find the people who actually saw something and can testify. There's nothing wrong with talking to people to figure out who knows things, and see how stories changed when they were told to different people, so you can more fully understand what happened. How this applies to your main question -- It might be very difficult to use a DNA database company results in a US court because you might have to involve a ton of witnesses to vouch for every part of the process. Suppose the defense asked, "But how do we know the post office didn't mix up different samples that day!?" You would be forced to either (a) have the USPS provide testimony establishing a full chain of custody, or (b) just test the defendant now to verify the match. It will always be easier to do (b), so I'd guess[1] everyone just skips to that step. [0] Even FPT has exceptions... [1] Maybe there are other procedural ways to approach this that are more common now, I haven't been involved in cases like these or researched it specifically, my criminal procedure knowledge is getting really dated so I might be wrong here.
    - vageli 7y ago
      > > Anything that guides an investigation is supposed to be admissable evidence or else you get into fruit of the poisonous tree territory, which is illegal. > Slight correction here. > The FPT doctrine makes it so most[0] evidence obtained illegally cannot be admitted. It doesn't work in reverse, it does not imply that all inadmissible evidence is illegal. > For example, the first half of many investigations is full of inadmissible hearsay, before you narrow in on what happened and find the people who actually saw something and can testify. There's nothing wrong with talking to people to figure out who knows things, and see how stories changed when they were told to different people, so you can more fully understand what happened. > How this applies to your main question -- > It might be very difficult to use a DNA database company results in a US court because you might have to involve a ton of witnesses to vouch for every part of the process. Suppose the defense asked, "But how do we know the post office didn't mix up different samples that day!?" You would be forced to either (a) have the USPS provide testimony establishing a full chain of custody, or (b) just test the defendant now to verify the match. It will always be easier to do (b), so I'd guess[1] everyone just skips to that step. I never thought of this but it would be surprising if the USPS _didn't_ maintain some sort of chain of custody of mail items, at least at the bag level or whatever unit they use.
- 2rsf 7y ago
  "unbelievable" on Netflix is a good example of such leads- family tree DNA leads to two brothers
SamReidHughes 7y ago
If you have somebody in custody, you can double-check the DNA record with a new cheek swab.
- vkou 7y ago
  The problem with fishing expeditions on DNA databases is that when you run a 'one in a million false positive' test against a database of 300,000,000 people, you're going to get 300 false positives. More than one of those suckers just might not have an alibi.
  - smnrchrds 7y ago
    I am curious about the actual false positive rate and how they compound. To use your hypothetical number, if the false positive rate is one in a million per test, if law enforcement tests your DNA sample against 700,000 samples from crime scenes, there is a 50% chance at least one of them will be a match due to false positive [1]. That is much scarier than what one in a million suggests. [1] (1 - 1e-6) ^ 700,000 = 49.6 % chance of no false positive match
  - dmckeon 7y ago
    Or you now have 299,999,700 probable negatives, and 300 possible positives to review for motive, method, and opportunity before you start looking at/for alibis.
    - nothal 7y ago
      Unless you've got a cold case, that seems like more potential suspects than a general person may reasonably have.
    - jessaustin 7y ago
      Oh yeah, lots of American police want to work this hard; there's probably five or six of them at least. What most police will do instead is arrest the first name on the list. When she or he documents an alibi, they'll arrest the second name on the list. Eventually, some poor bastard who lives in the same state will have gone hiking alone the day of the crime, or stayed home and slept after a week of overtime, or whatever. Unless there is a statistician on the jury, that person is going to prison.
blotter_paper 7y ago
Resampling DNA before conviction would fix the specific issue of the digital record being subject to tampering, I kind of assume this is done already. The real nightmare is that we might be right around the corner from DNA being writable to the extent that you could make mock DNA to plant at a crime-scene/evidence-locker, and there might be a couple awkward decades where the courts believe the FBI when they claim to have found DNA matches (just like that time they systematically pretended they could identify hairs, and convicted people of murder based on hairs that were literally from dogs in some cases). We'll catch on eventually if they try it, but it would suck for those of us convicted on falsified evidence. I wouldn't be so paranoid about that possibility if they hadn't lied about the dog hairs for decades.
- Terr_ 7y ago
  > right around the corner from DNA being writable Why bother when it's trivial to copy existing DNA? The evildoer just needs to get a tiny sample from someone who'd made a decent frame. Sure, then you've got the problem of how to create a DNA-bearing artifact that'll fool forensics -- a spilled puddle of pure chromosomes would be weird -- but that'd be true in either case.
  - rtkwe 7y ago
    I've read a couple books where the opposite was done. Intentionally dump huge amounts of DNA into the area to make any tracing pointless. One amusing and gross way was vacuuming bus seats for the material.
    - jacquesm 7y ago
      Keyboards are a great source of material. They accumulate no end of crap over time.
      - pimmen 7y ago
        I wonder how often public library keyboards are cleaned, or the ones in university computer labs. When I was in college pulling all nighters in the computer lab I regularly saw the lab being cleaned, but I can't remember ever seeing the keyboards getting dusted off, let alone wiped off with disinfectants. Go to two or three libraries in different corners of town, get what you want from the keyboards, and you should have quite the collection of DNA.
detail-oriented 7y ago
It seems like any competent defense attorney would insist on resampling, or alternatively insist this evidence thrown out duebto lack of chain of custody. Signed, not a lawyer.
- jacquesm 7y ago
  Insisting on resampling would be stupid, it will match twice that is not the problem. But if you insist on resampling then you are giving the evidence more weight than it can bear, much better to show that statistically it does not have much weight at all even if it matches (once, twice or more is not relevant). The cold cases broken open are the ones that are left after all the other methods have already been exhausted. Sure, some of those might have remained unsolved if not for this method. But that does nothing to show the method by itself works better than all the other police work, for that to be concluded you'd have to compare with all the cases that were solved with ordinary police work and then to conclude that if all of them were first attempted to be solved with this method that the total outcome would be an improvement. That seems unlikely. So for a very small fraction of extra cases solved a very large change in evidence gathering methods and dragnet style fishing for suspects does not seem to be worth it to me.
  - detail-oriented 7y ago
    Stupid if your client is guilty and you trust the database, not so stupid if your client insists they are innocent and the database governance processes are suspect.
    - jacquesm 7y ago
      That test will run the same way twice unless it has been tampered with, you'd have to be pretty sure before taking a gamble on that. The chances of a false positive are >> the chances of database tampering, why attack the harder target?
hugh4life 7y ago
Law enforcement in the US could build a pretty powerful genetic genealogy database just using their own DNA.
bayesian_horse 7y ago
I know that members of the military already have been entered into DNA databases, and there are reasons to do this with police officers and firefighters. Mostly to identify them postmortem. I don't subscribe to DNA information being a secret. It tends to be "secret" in the sense that it is non-trivial to obtain. But you leave behind a trail of DNA everywhere. Ultimately, it cannot be held secret. Therefor it is more important to regulate the use of such information, for example to prevent discrimination.
- nyolfen 7y ago
  i suspect the military/leo databases are not the ones being searched in criminal cases
  - Bedon292 7y ago
    In fact when your DNA is taken for the military database it is explicitly stated that it will not be used for criminal cases. If anyone managed to search the database, that would certainly get thrown out by a court.
    - vageli 7y ago
      > In fact when your DNA is taken for the military database it is explicitly stated that it will not be used for criminal cases. If anyone managed to search the database, that would certainly get thrown out by a court. I wouldn't be so sure. Evidence observed during the execution of a warrant against the incorrect property is still valid and admissable, for example. Not saying this kind of thing applies in this specific case but thought the idea worth mentioning.
    - bayesian_horse 7y ago
      Aren't there exceptions when there is a reasonable cause to suspect a member of the military?

foota 7y ago

I don't think these are typically used (or could be used) to convict someone, I think it's mostly used to guide investigations.

astura 7y ago
This is correct, it's used to find suspects, not to convict anyone.
- geggam 7y ago
  AKA fishing
  - gbrown 7y ago
    If done right, spear fishing. I'm a privacy guy, but the science really is there to use DNA to narrow a list of suspects. You can't say the same for much of forensic science, or for that matter mass surveillance technologies.
    - tareqak 7y ago
      However, the list of suspects can still lack the actual criminal(s), but still contain an innocent with poor, but true alibi.
      - tbyehl 7y ago
        Here's an actual case of an innocent person who faced charges and a high probability of losing their freedom due to DNA transference: https://www.wired.com/story/dna-transfer-framed-murder/ https://www.wired.com/story/dna-transfer-framed-murder/ The take-away is that shed skin cells containing DNA can migrate and a DNA match from that type of evidence shouldn't be relied on as proof of anything. To my view, the combination of DNA transference, advancing DNA collection / analysis techniques, the mere existence of DNA databases, and familial searches are absolutely terrifying.
        gbrown 7y ago
        Good counterpoint, definitely an issue. When the police find macroscopic quantities of bodily fluids, however, it would seem to be madness not to use the evidence.
        tbyehl 7y ago
        Absolutely. I do question if society is better off catching a few more criminals through these databases and familial matching vs the potential for innocents to be imprisoned based on nothing more than a DNA match against skin cells. I'm also not too fond of the idea of my relatives' DNA being used to draw suspicion to another relative just because someone's DNA wound up in a database. To me it's just another one of those things (ALPRs, all the compilations of "it's just metadata") that erode our privacy and give the state a great deal of power for relatively little benefit to the people. All crimes don't get solved, all criminals don't get caught, and in a society where everyone's a law-breaker because there are too many laws to know them all and so many of them are dumb, that's how things should be.
monocasa 7y ago
Why wouldn't they be allowed to be used? Anything that guides an investigation is supposed to be admissable evidence or else you get into fruit of the poisonous tree territory, which is illegal. Not saying it wouldn't happen still, but they wouldn't be talking about using it in that case. It'd be like with stingrays where they publicly claim that they got a tip from a confidential informant and drop cases on anyone who gets close to the truth so the never actually get a judge to tell them they can't do it.
- brownbat 7y ago
  > Anything that guides an investigation is supposed to be admissable evidence or else you get into fruit of the poisonous tree territory, which is illegal. Slight correction here. The FPT doctrine makes it so most[0] evidence obtained illegally cannot be admitted. It doesn't work in reverse, it does not imply that all inadmissible evidence is illegal. For example, the first half of many investigations is full of inadmissible hearsay, before you narrow in on what happened and find the people who actually saw something and can testify. There's nothing wrong with talking to people to figure out who knows things, and see how stories changed when they were told to different people, so you can more fully understand what happened. How this applies to your main question -- It might be very difficult to use a DNA database company results in a US court because you might have to involve a ton of witnesses to vouch for every part of the process. Suppose the defense asked, "But how do we know the post office didn't mix up different samples that day!?" You would be forced to either (a) have the USPS provide testimony establishing a full chain of custody, or (b) just test the defendant now to verify the match. It will always be easier to do (b), so I'd guess[1] everyone just skips to that step. [0] Even FPT has exceptions... [1] Maybe there are other procedural ways to approach this that are more common now, I haven't been involved in cases like these or researched it specifically, my criminal procedure knowledge is getting really dated so I might be wrong here.
  - vageli 7y ago
    > > Anything that guides an investigation is supposed to be admissable evidence or else you get into fruit of the poisonous tree territory, which is illegal. > Slight correction here. > The FPT doctrine makes it so most[0] evidence obtained illegally cannot be admitted. It doesn't work in reverse, it does not imply that all inadmissible evidence is illegal. > For example, the first half of many investigations is full of inadmissible hearsay, before you narrow in on what happened and find the people who actually saw something and can testify. There's nothing wrong with talking to people to figure out who knows things, and see how stories changed when they were told to different people, so you can more fully understand what happened. > How this applies to your main question -- > It might be very difficult to use a DNA database company results in a US court because you might have to involve a ton of witnesses to vouch for every part of the process. Suppose the defense asked, "But how do we know the post office didn't mix up different samples that day!?" You would be forced to either (a) have the USPS provide testimony establishing a full chain of custody, or (b) just test the defendant now to verify the match. It will always be easier to do (b), so I'd guess[1] everyone just skips to that step. I never thought of this but it would be surprising if the USPS _didn't_ maintain some sort of chain of custody of mail items, at least at the bag level or whatever unit they use.
2rsf 7y ago
"unbelievable" on Netflix is a good example of such leads- family tree DNA leads to two brothers

SamReidHughes 7y ago

If you have somebody in custody, you can double-check the DNA record with a new cheek swab.

vkou 7y ago
The problem with fishing expeditions on DNA databases is that when you run a 'one in a million false positive' test against a database of 300,000,000 people, you're going to get 300 false positives. More than one of those suckers just might not have an alibi.
- smnrchrds 7y ago
  I am curious about the actual false positive rate and how they compound. To use your hypothetical number, if the false positive rate is one in a million per test, if law enforcement tests your DNA sample against 700,000 samples from crime scenes, there is a 50% chance at least one of them will be a match due to false positive [1]. That is much scarier than what one in a million suggests. [1] (1 - 1e-6) ^ 700,000 = 49.6 % chance of no false positive match
- dmckeon 7y ago
  Or you now have 299,999,700 probable negatives, and 300 possible positives to review for motive, method, and opportunity before you start looking at/for alibis.
  - nothal 7y ago
    Unless you've got a cold case, that seems like more potential suspects than a general person may reasonably have.
  - jessaustin 7y ago
    Oh yeah, lots of American police want to work this hard; there's probably five or six of them at least. What most police will do instead is arrest the first name on the list. When she or he documents an alibi, they'll arrest the second name on the list. Eventually, some poor bastard who lives in the same state will have gone hiking alone the day of the crime, or stayed home and slept after a week of overtime, or whatever. Unless there is a statistician on the jury, that person is going to prison.

blotter_paper 7y ago

Resampling DNA before conviction would fix the specific issue of the digital record being subject to tampering, I kind of assume this is done already. The real nightmare is that we might be right around the corner from DNA being writable to the extent that you could make mock DNA to plant at a crime-scene/evidence-locker, and there might be a couple awkward decades where the courts believe the FBI when they claim to have found DNA matches (just like that time they systematically pretended they could identify hairs, and convicted people of murder based on hairs that were literally from dogs in some cases). We'll catch on eventually if they try it, but it would suck for those of us convicted on falsified evidence. I wouldn't be so paranoid about that possibility if they hadn't lied about the dog hairs for decades.

Terr_ 7y ago
> right around the corner from DNA being writable Why bother when it's trivial to copy existing DNA? The evildoer just needs to get a tiny sample from someone who'd made a decent frame. Sure, then you've got the problem of how to create a DNA-bearing artifact that'll fool forensics -- a spilled puddle of pure chromosomes would be weird -- but that'd be true in either case.
- rtkwe 7y ago
  I've read a couple books where the opposite was done. Intentionally dump huge amounts of DNA into the area to make any tracing pointless. One amusing and gross way was vacuuming bus seats for the material.
  - jacquesm 7y ago
    Keyboards are a great source of material. They accumulate no end of crap over time.
    - pimmen 7y ago
      I wonder how often public library keyboards are cleaned, or the ones in university computer labs. When I was in college pulling all nighters in the computer lab I regularly saw the lab being cleaned, but I can't remember ever seeing the keyboards getting dusted off, let alone wiped off with disinfectants. Go to two or three libraries in different corners of town, get what you want from the keyboards, and you should have quite the collection of DNA.

detail-oriented 7y ago

It seems like any competent defense attorney would insist on resampling, or alternatively insist this evidence thrown out duebto lack of chain of custody. Signed, not a lawyer.

jacquesm 7y ago
Insisting on resampling would be stupid, it will match twice that is not the problem. But if you insist on resampling then you are giving the evidence more weight than it can bear, much better to show that statistically it does not have much weight at all even if it matches (once, twice or more is not relevant). The cold cases broken open are the ones that are left after all the other methods have already been exhausted. Sure, some of those might have remained unsolved if not for this method. But that does nothing to show the method by itself works better than all the other police work, for that to be concluded you'd have to compare with all the cases that were solved with ordinary police work and then to conclude that if all of them were first attempted to be solved with this method that the total outcome would be an improvement. That seems unlikely. So for a very small fraction of extra cases solved a very large change in evidence gathering methods and dragnet style fishing for suspects does not seem to be worth it to me.
- detail-oriented 7y ago
  Stupid if your client is guilty and you trust the database, not so stupid if your client insists they are innocent and the database governance processes are suspect.
  - jacquesm 7y ago
    That test will run the same way twice unless it has been tampered with, you'd have to be pretty sure before taking a gamble on that. The chances of a false positive are >> the chances of database tampering, why attack the harder target?

hugh4life 7y ago

Law enforcement in the US could build a pretty powerful genetic genealogy database just using their own DNA.

bayesian_horse 7y ago

I know that members of the military already have been entered into DNA databases, and there are reasons to do this with police officers and firefighters. Mostly to identify them postmortem. I don't subscribe to DNA information being a secret. It tends to be "secret" in the sense that it is non-trivial to obtain. But you leave behind a trail of DNA everywhere. Ultimately, it cannot be held secret. Therefor it is more important to regulate the use of such information, for example to prevent discrimination.

nyolfen 7y ago
i suspect the military/leo databases are not the ones being searched in criminal cases
- Bedon292 7y ago
  In fact when your DNA is taken for the military database it is explicitly stated that it will not be used for criminal cases. If anyone managed to search the database, that would certainly get thrown out by a court.
  - vageli 7y ago
    > In fact when your DNA is taken for the military database it is explicitly stated that it will not be used for criminal cases. If anyone managed to search the database, that would certainly get thrown out by a court. I wouldn't be so sure. Evidence observed during the execution of a warrant against the incorrect property is still valid and admissable, for example. Not saying this kind of thing applies in this specific case but thought the idea worth mentioning.
  - bayesian_horse 7y ago
    Aren't there exceptions when there is a reasonable cause to suspect a member of the military?