4 ms·

DNA in the dock: flawed techniques send innocent people to prison

63 points by kawera 9y ago

libeclipse 9y ago
I'm wondering if it could ever get to the point where you should never give away your old clothes in case the next owner dies and you're incarcerated for murder. Incineration-As-A-Service anyone?
avs733 9y ago
This seems like an ongoing problem with science and the criminal justice system, especially in the US. Science, and the trustworthiness of science, become an object of adversarial argument by non experts that have directly opposing interest, and which often face large disparities in resources with which to make that argument. I had a discussion years ago at a conference with an EFF member that they really ought to (obviously easy for me to suggest) hold training sessions for judges on the basics of how technology and the internet works. Otherwise, the courts seem enormously susceptible to bad analogies ('an I.P address is just like a physical mailing address') that are used in place of actual evidence.
deleted 9y ago
[deleted]
acomjean 9y ago
I took a genomics class. We had a guest lecture by: Frederick R. Bieber about medical Forenics. Fascinating stuff. Its interesting the way they try to identify people is they pick 13 locations (more as of this year, the article says 16 locations for england) then count what are known as "Short tandem repeats"(STR). These STR markers exist on many chromosomes and are short sequences that repeat, everyone has a different count. (there is a standard for these locations in the US called CODIS: http://strbase.nist.gov/fbicore.htm http://strbase.nist.gov/fbicore.htm) If you have good reads the probability of a random match is in 1 in 594 trillion. Its complicated as the DNA can degrade and the reads can be not so good. Some places allow Forensic DNA analysis by data mining, in which case you may find relatives of a criminal. Some states require felons DNA to be added to the database. This can be searched though its controversial and familial searches are blocked by some states. One case helped by this was Lonnie Franklin Jr. aka the "grim sleeper" who took a long time to apprehend. https://en.wikipedia.org/wiki/Grim_Sleeper https://en.wikipedia.org/wiki/Grim_Sleeper "Police had found no exact match between DNA found at the crime scenes and any of the profiles in California's DNA profile database, so they searched the database for stored profiles that demonstrated sufficient similarity to allow police to infer a familial relationship. They found similar DNA belonging to Franklin's son, Christopher, who had been convicted of a felony weapons charge. " Exonerations are possible using dna too: http://www.brandeis.edu/investigate/innocence-project/dennis-maher.html http://www.brandeis.edu/investigate/innocence-project/dennis... DNA analysis is just a tool, it can also lead to post conviction exonerations. I think its best used a evidence for building a case, not having the whole weight of the case on just DNA evidence.
dsfyu404ed 9y ago
The DA has an incentive to convict people. All the people who supply the evidence have incentives to help out. Who gets convicted isn't all that important as long as there's a pretty good correlation between a crime being convicted and someone being punished. Doing "my PHD is dependent on this and I'm not going to f-it up" work is time consuming and expensive. Whether the lab and investigative work done is high quality or sloppy it doesn't matter as long as the strong correlation between a crime being committed and someone being punished remains. Something something metrics and targets.

63 points by kawera 9y ago

I'm wondering if it could ever get to the point where you should never give away your old clothes in case the next owner dies and you're incarcerated for murder. Incineration-As-A-Service anyone?

avs733 9y ago

This seems like an ongoing problem with science and the criminal justice system, especially in the US. Science, and the trustworthiness of science, become an object of adversarial argument by non experts that have directly opposing interest, and which often face large disparities in resources with which to make that argument. I had a discussion years ago at a conference with an EFF member that they really ought to (obviously easy for me to suggest) hold training sessions for judges on the basics of how technology and the internet works. Otherwise, the courts seem enormously susceptible to bad analogies ('an I.P address is just like a physical mailing address') that are used in place of actual evidence.

deleted 9y ago

[deleted]

acomjean 9y ago

I took a genomics class. We had a guest lecture by: Frederick R. Bieber about medical Forenics. Fascinating stuff. Its interesting the way they try to identify people is they pick 13 locations (more as of this year, the article says 16 locations for england) then count what are known as "Short tandem repeats"(STR). These STR markers exist on many chromosomes and are short sequences that repeat, everyone has a different count. (there is a standard for these locations in the US called CODIS: http://strbase.nist.gov/fbicore.htm http://strbase.nist.gov/fbicore.htm) If you have good reads the probability of a random match is in 1 in 594 trillion. Its complicated as the DNA can degrade and the reads can be not so good. Some places allow Forensic DNA analysis by data mining, in which case you may find relatives of a criminal. Some states require felons DNA to be added to the database. This can be searched though its controversial and familial searches are blocked by some states. One case helped by this was Lonnie Franklin Jr. aka the "grim sleeper" who took a long time to apprehend. https://en.wikipedia.org/wiki/Grim_Sleeper https://en.wikipedia.org/wiki/Grim_Sleeper "Police had found no exact match between DNA found at the crime scenes and any of the profiles in California's DNA profile database, so they searched the database for stored profiles that demonstrated sufficient similarity to allow police to infer a familial relationship. They found similar DNA belonging to Franklin's son, Christopher, who had been convicted of a felony weapons charge. " Exonerations are possible using dna too: http://www.brandeis.edu/investigate/innocence-project/dennis-maher.html http://www.brandeis.edu/investigate/innocence-project/dennis... DNA analysis is just a tool, it can also lead to post conviction exonerations. I think its best used a evidence for building a case, not having the whole weight of the case on just DNA evidence.

dsfyu404ed 9y ago

The DA has an incentive to convict people. All the people who supply the evidence have incentives to help out. Who gets convicted isn't all that important as long as there's a pretty good correlation between a crime being convicted and someone being punished. Doing "my PHD is dependent on this and I'm not going to f-it up" work is time consuming and expensive. Whether the lab and investigative work done is high quality or sloppy it doesn't matter as long as the strong correlation between a crime being committed and someone being punished remains. Something something metrics and targets.