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Forensics Gone Wrong: When DNA Snares the Innocent (2016)

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Re: Forensics Gone Wrong: When DNA Snares the Innocent (2016)

#41

Post by toast0 »

Lord-Jobo wrote: post #10
arcbyte wrote: post #6

Earlier quoted context omitted.

I think there's more work we can do to balance the power of individual defendants against the state, but the adversarial justice system is the most accurate and effective system for mediating public safety, punishment, and revenge ever developed in the history of the world.

The main concern here is that the system is being nearly entirely bypassed. Literally 98% of cases plea out^1, bypassing the entire system of court procedure that is supposed to resolve these issues. 1: https://www.npr.org/2023/02/22/1158356619/plea-bargains-crim...

You're already quite a bit down the funnel if you're talking about % of cases.

If the feds have a high bar before opening a case, it's not immediately unreasonable that most of the cases are managed with plea bargains.

It might be better to look at the process beginning with arrests or beginning with investigations.

Re: Forensics Gone Wrong: When DNA Snares the Innocent (2016)

#42

Post by jMyles »

karmakaze wrote: post #21

> [...] he confessed after a series of lengthy interrogations that several experts have described as coercive. Police found plenty of male DNA at the scene, and it did not match Tapp's. But the prosecutor and jury believed his confession. This story isn't even about DNA evidence.

It's true. People reliably confess to crimes they did not commit. It's just another dead canary in the cages of our justice system.

Re: Forensics Gone Wrong: When DNA Snares the Innocent (2016)

#44

Post by jerf »

jansan wrote: post #31
bradyd wrote: post #29

Earlier quoted context omitted.

There was also the case where a DNA test of a woman's children showed that they did not share any of her DNA. Social Services was threatening to take them away from her. When she had another child, the court ordered an officer to be present during the birth and collect DNA from both of them at that time. Even still the DNA "proved" she was not the mother. It was only after another similar case was discovered that the…

"Trust the science" always must be taken with a grain of salt.

This is another example of the "probability noise floor" I mentioned yesterday: https://news.ycombinator.com/item?id=39112610

You can't be one-in-a-trillion confident about any particular DNA result, even if that's what the nominal probability from the DNA analysis itself seems to say, because it is objectively observable that there are plenty of other sources of errors of all sorts. You can only get down to that "noise floor" of probabilities. This can still be a very useful result, but it's important to not let it be any more important that it deserves.

Even if you have a magic machine that you can point at someone and it goes "boop" if they are guilty, you still must consider the probability that someone faked the "boop", or has swapped in a different shell that looks the same but makes the same "boop" when someone remotely triggers it or that the speaker was broken so even though the magic machine tried to "boop" nobody could hear it. All of these are quite realistic and of a much higher probability than the magic machine existing in the first place.

(This is also arguably the root problem with the still-popular "The computer said it so it must be true". Even if you assume the computer really is 100% accurate, which itself is a transparently false proposition when examined in daylight, there's still plenty of other reasons why one should not give the computer too much confidence.)

Re: Forensics Gone Wrong: When DNA Snares the Innocent (2016)

#45

Post by NoMoreNicksLeft »

karmakaze wrote: post #21

> [...] he confessed after a series of lengthy interrogations that several experts have described as coercive. Police found plenty of male DNA at the scene, and it did not match Tapp's. But the prosecutor and jury believed his confession. This story isn't even about DNA evidence.

Confessions need to be made inadmissible in court as evidence. All state legislatures have the power to make that so, as does Congress at the federal level. The judicial system could do it too, in theory, but never will.

Confessions could still be used by police as leads. While all "eyewitness testimony" is defective evidence, confessions are the most defective of all. Humans have weird psychology, but the psychology around confessions is the weirdest of all. It's why it's been exploited by the Catholic religion (and others). It causes strange (and not always unpleasant) emotions in those confessing, those hearing the confession, and even those confessing falsely. It causes them in those who confess because they were coerced, it causes them in those who choose to falsely confess without coercion. To those who are familiar with them, those pleasant feelings can become an irresistible temptation to falsely confess.

On top of that, it's been what, nearly 70 years since shows like the Twilight Zone introduced the idea to everyone that in unusual circumstances we might have done things we don't even remember. So when someone starts to break after long and even tortuous interrogations, they might themselves start to worry that they are guilty and their memories are faulty.

Re: Forensics Gone Wrong: When DNA Snares the Innocent (2016)

#47

Post by jacquesm »

jansan wrote: post #31
bradyd wrote: post #29

Earlier quoted context omitted.

There was also the case where a DNA test of a woman's children showed that they did not share any of her DNA. Social Services was threatening to take them away from her. When she had another child, the court ordered an officer to be present during the birth and collect DNA from both of them at that time. Even still the DNA "proved" she was not the mother. It was only after another similar case was discovered that the…

"Trust the science" always must be taken with a grain of salt.

It depends on the strength of the science and this is a real problem with unsettled science: it is routinely used to sell pipe dreams and silver bullets to officials without further qualification or caveats. That's why you see AI used in law enforcement right now when it really isn't even close to reliable enough to be used in such a potentially life changing setting.

Re: Forensics Gone Wrong: When DNA Snares the Innocent (2016)

#48

Post by kstenerud »

karmakaze wrote: post #21

> [...] he confessed after a series of lengthy interrogations that several experts have described as coercive. Police found plenty of male DNA at the scene, and it did not match Tapp's. But the prosecutor and jury believed his confession. This story isn't even about DNA evidence.

[flagged]

Re: Forensics Gone Wrong: When DNA Snares the Innocent (2016)

#49

Post by [deleted] »

karmakaze wrote: post #21

> [...] he confessed after a series of lengthy interrogations that several experts have described as coercive. Police found plenty of male DNA at the scene, and it did not match Tapp's. But the prosecutor and jury believed his confession. This story isn't even about DNA evidence.

[deleted]
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