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America's 250th DNA exoneration: How often is wrong person sent to prison? (reason.com)
48 points by cwan on Feb 9, 2010 | hide | past | favorite | 39 comments


> Most prosecutors fight requests for post-conviction DNA testing.

Knowing human nature, this is understandable - there's a tendency to think that once a "fight" has been won, it should stay won. But it's also disturbing: does this tendency cause people to actively want to imprison innocent people?

I've read of similar cases, where prisoners due to be executed have last-minute appeals due to new evidence / etc., but state governors press ahead with the execution so that they can politically appear to be "tough on crime". The problem being that the appearance of being tough on crime seems to come from killing someone, rather than actually ensuring justice is done.


The average person is, for no good reason whatsoever, certain that they will never be falsely accused of a crime. They also believe that anyone who has drawn the attention of the police must have done something to deserve it, and are fine with a few 'innocent' people slipping through the cracks if it means more safety overall. Anti-intellectualism is dangerous, and it is global right now. The principles the US justice system were built on - innocent until proven guilty, acknowledging the possibility of fallibility on the part of the prosecution, etc - are viewed by the general public as loopholes that keep criminals on the street. The simple idea that we would operate based upon principles, regardless of what they are, is viewed as wrong. There is no way to reason with these viewpoints because they reject reason as their basis.


> The problem being that the appearance of being tough on crime seems to come from killing someone, rather than actually ensuring justice is done.

Innocent people die in prison every day, typically in the infirmary.

If you're innocent, you're better off being given the death penalty because that's your best chance for decent review.


what's more disturbing is that states allow people to be executed based on circumstantial evidence in the first place


If 17 people on death row out of less than 4000 were innocent, then clearly we executed innocent people prior to DNA testing. So, perhaps we should increase the level of evidence required to kill someone.


We've pretty clearly executed the wrong people since there has been DNA testing too. Grisham wrote a non-fiction about it "The Innocent Man." There is some heavy stuff in it.

I guess I'm kind of torn, I think we want prosecutors to be aggressive when they go to court. One the case is over, it seems like they need to be removed, their opinion on DNA testing or other things should no longer be needed. DNA or not, how do you convict an innocent man of a crime he didn't do? Just incredibly bad luck and circumstantial evidence? I don't buy that, not if he has a good defense which he's entitled to. The other thing in this Grisham book is that a lot of the mis-convicted folks are poorer, maybe not the most emotionally balanced, and often kind of outsiders in their communities (like the black guy in the all white town, or the dark haired gothic guy in the rural community) and there is more than just DNA evidence that have been perverted. To have any reasonable oversight or feed back into the system, you'd have to remove the prosecutor once his job is done.


Or, you know, not kill them.


I've gotten to the point that I think the death penalty should be abolished and substituted with life / guaranteed no parole. I am not morally opposed to the death penalty, but I believe that we are not perfect and shouldn't 'accidentally' execute anyone. Plus, it is a whole lot cheaper to keep someone in prison for life then the cost to governments for a full run through the appeals process.

In short, its a badly designed, error prone, high cost process.


Or... y'know... stop killing them...


> Knowing human nature, this is understandable - there's a tendency to think that once a "fight" has been won, it should stay won. But it's also disturbing: does this tendency cause people to actively want to imprison innocent people?

It's not that they want to imprison innocents; it's a prosecutor's job to get the defendant convicted no matter what, whether or not they personally believe the defendant is guilty. They are simply acting as their job calls for (the conflicting prosecution and defense attorneys in theory bringing about the truth), because until now you could never be 100% sure. '100% sure' and 'our legal system' do not go well together.

P.S. Don't invoke the argument over the ethically wrong claiming 'oh I was just doing my job'- this is different; we WANT the prosecutor to behave like that, even if he feels or even knows the defendant is innocent. It's what (in theory anyway) makes the system work.


I agree that an adversarial system is an effective system for truth discovery. However, in order for it to be an effective and unbiased truth discovery system, there need to be a couple of restraints on both parties, like fully sharing information and evidence. Because prosecutors are incentivized to achieve prosecutions rather than truth, they are encouraged to push (or break) those constraints. While the adversarial system is reasonably effective in theory, the fact that one side is encouraged to miss the forest (truth) for the trees (conviction) has degenerate effects on edge cases.

The other major problem is advocacy gap. An ambitious prosecutor looking to jump-start his career will provide unbalanced advocacy compared to a pro-bono defense lawyer.


> the fact that one side is encouraged to miss the forest (truth) for the trees (conviction) has degenerate effects on edge cases

You have to take into account the fact that the defense is encouraged to miss the forest (truth) for the trees (exoneration) as well.


True. However, rather than balancing out, in practice that doubles the number of edge cases.


We want the prosecutor to decide which cases to prosecute, and which to abandon because it's not likely that the accused is guilty. What you say you want is actually horrible and unnecessary, unless you just mean that the prosecutor should proceed if his personal certainty of guilt is only say, 80%, before having encountered all the available evidence; that's fine, because trials should have some truth-finding value, and make all the available evidence known to the prosecution and defense (even if judges can rule out some evidence). At the end of a trial (after all the evidence and testimony is known), in theory, the prosecution and defense should have a pretty good idea of the likelihood of guilt, but we excuse them for playing the game to its conclusion - playing to win even when they suspect their side is wrong: either lying, or deluding themselves with biased/self-interested thinking.

In the event a prosecutor is pretty sure the defendant is innocent AND that they can probably get a conviction, I'd like to see them abandon their case (I don't know if this allowed, but they could certainly argue to a jury or judge that the person is innocent), but I understand that it's not required, and I don't consider them evil unless they go further and try to block appeals, or conceal exculpatory evidence.


You realize what you're asking for here is that the prosecutor decide who is innocent and who to fully prosecute, i.e. who is guilty. That completely, or at least partially, negates the idea that the jury of your peers should do the deciding. As soon as the lawyers start making those kinds of choices, it's not (all) in the jury's hands anymore.

Perhaps you might suggest the prosecution is in the best position to know. Perhaps you might suggest that if the prosecution is 80% certain of innocence, that clearly the defendant should be found innocent. But, according to our law, (unless I grossly misunderstand them) it is not his choice to make.


It's not that they want to imprison innocents; it's a prosecutor's job to get the defendant convicted no matter what, whether or not they personally believe the defendant is guilty.

I think that in some cases, they want to imprison someone, and show that they are doing their job, even if they have serious doubts about the guilt of the person they are imprisoning.

In any case, refusing to allow DNA testing that can categorically establish the guilt or innocence of someone seems to me to be unethical.


"Any prosecutor can convict a guilty man: it takes a great prosecutor to convict an innocent man." --Melvyn Bruder

(http://www.errolmorris.com/film/tbl_transcript.html)


> we WANT the prosecutor to behave like that, even if he feels or even knows the defendant is innocent.

Err... no. There are plenty of genuinely guilty people to go after without knowingly attempting to imprison innocent people.


It's one thing to uphold an oath to zealously represent the state and the victim, but it's another to preemptively repudiate a fact finding effort. I feel it is much more about preservation of ego and judicial economy.


I don't agree on personal levels that what they are doing is right; I just believe it is them zealously representing the state and the victim- via the legal channels provided them. Of course you'll have bad apples, but...

Legal system isn't always all that cut and dried, you can't always go straight for the throat. Many of the big crime bosses and such were apparently brought down on tax evasion!

I'm sure there's been more than one time stymying a fact finding effort has helped send a guilty man to jail. It's not all cut and dried. I gather my views are unpopular, but hey, oh well.


According to a new report by the Innocence Project, those 250 prisoners served 3,160 years between them; 17 spent time on death row. Remarkably, 67 percent of them were convicted after 2000—a decade after the onset of modern DNA testing.

My guess: more often than not, it's simply an issue of legal politics. Investigators or prosecutors have pressure put on them to lock up somebody . . . anybody as a means to close a case or re-direct media attention. Getting the actual culprit almost seems to be of secondary importance. Loose killers/rapists demand much more media attention than those who've been put behind bars, and having such people on the loose means that people might portray their local law enforcement officials as "not doing their jobs".

@asolove: Well, there's that Florida man who was exonerated after 35 years in prison, thanks to DNA evidence:

http://crimesandjustice.com/james-bain-freed-35yrs-prison-in...


Also, by all accounts I've read, forensic science isn't exactly held to scientific standards--they use so many tests that have never been experimentally evaluated, it could more accurately be called forensic folklore. Since judges and lawyers are seldom clueful about the natural sciences, often very strong evidence is ignored in favor of the word of an "expert."


Or witnesses.


I'm taking the intro to Criminal Justice course this semester at my local community college at night, I've had 2 classes so far, so take this with a grain of salt. But in our last class we were told that the majority of wrongful convictions have been due to incorrect eye witness identification. Whether this was due to a actual mistake on behalf of the witness, or due to mistakes in how the photo selection or lineup was conducted by the law enforcement officer.


> The certainty of DNA testing means we can be positive the 250 cases listed in the Innocence Project report didn't commit the crimes for which they were convicted

This is simply not true. Matching DNA against the defendant is basically 100%, but that doesn't take into account the circumstances of the case and where that DNA fits into the evidentiary chain. All the DNA has to do is provide reasonable doubt. It does not prove innocence. Indeed, contrary to the claim, it is virtually certain that some of the convicted in the overturned cases did commit their crimes.

Because of the political will behind resurrected DNA cases, the circumstantial link doesn't need to be very strong to have a case overturned via DNA.


And of course, there is always Bayes to take into account. If a jury hears that there's only a "one in a million" chance that a DNA match would happen randomly, they may overweigh this fact, when put up against e.g. a city of 3 million people - which, assuming no other evidence and that the criminal is known to be from the city, would make the chance of this guy being the guilty party only 1 in 3.


Isn't it true that using Bayesian inference one should conclude that given a positive DNA match that it is more likely you have a false positive than an actual match? That isn't there are greater likelihood that there was a mistake in the DNA testing result than you actually find a match? :/


If the person who was tested was chosen at random from the population, then yes. But -- and this is an important point that somehow almost gets omitted when the usual examples of DNA evidence, medical tests, etc., are brought up -- when you're testing someone's DNA against samples from a crime scene, or testing whether a person has a rare disease, it's almost always because you already have evidence that brings Pr(they did it) or Pr(they have the disease) way above the baseline level. And in that case Pr(they did it | DNA evidence), or Pr(they have the disease | test result), may well be quite large.

(Of course that's not true if the person with matching DNA was found by some kind of search of a Vast DNA Database, or if the positive result on the medical test was the result of a mass screening exercise that tests everybody.)


That reasoning would only hold if you surveyed the DNA of everyone in that city, which is never the case.


No, you don't need to survey everyone in the city. Assume you instituted a DNA search, whereby you went from district to district and tested DNA until you got a match, the chance would still be only 1 in three, under the same assumptions.

And government policy here in the UK seems to be to retain the DNA of everyone that comes into contact with the state, so I expect it's only a matter of time until there will be chance collisions resulting in incorrect convictions.


OK, it only applies if you survey everyone in the city until you get a match. Same difference. Yes, things may be heading in that direction. That was not the original argument, though.


And if the DNA was every hint you had.


This article details not only the wrongful conviction, but wrongful execution of a Texan man accused of arson. It's a little long, but worth the read, as it really puts a human face on what a wrongful conviction can mean for someone. http://www.newyorker.com/reporting/2009/09/07/090907fa_fact_...


The one fact you will never hear when DNA results are being discussed: 1 out of every 100 DNA tests are bungled by the testing lab. Either through mistake, contamination of samples, whatever. So that "1 in X billion" odds they toss around should be viewed with that fact in mind. Oh, and you're not allowed to mention it in court. Ever. They're too afraid the jury will get confused.

(The book "Drunkard's Walk: How Randomness Rules Our Lives" contains all the details.)


I always wonder about this and chimera. Anyone know of cases where the right person was set free? http://www.thetech.org/genetics/ask.php?id=23


In Texas' next execution, the state is refusing to allow the remaining evidence to be DNA tested. You'd think we'd want to be as certain as possible that innocent people aren't getting executed...

http://www.texastribune.org/stories/2010/jan/28/dead-man-bal...


I believe you should be careful about pronouns. The "we" in "we'd want" must mean "the people of Texas", and when considered like that, isn't true. Polls show Texans overwhelmingly in favor of the death penalty, even when we (as in all of the US citizens) know that panalty is applied very unequally along racial and economic class lines.


Texans favor the death penalty, but I sincerely doubt that they favor executing innocent people. They may not want this guy to get any more chances to prove his innocence, but that would be due to broken logic, not the desire to execute innocents.


Convicted in 1976. My entire adult life, buried under a prison wall. So many kinds of people I've been, lives I've lead, so many people I've known, things I've done.




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