There is strong evidence and weak evidence.  And then there’s the jailhouse snitch, without question the worst evidence possible.  Cops and prosecutors know this, but love it anyway. Having concluded someone is guilty, but being unable to find evidence to support their belief, it’s like manna from heaven to the starving.

That it’s bad evidence, the sort most likely to falsely convict an innocent man, can’t shake their faith.  Adding to the unsavory mix is that the jailhouse snitch gives up his fellow prisoner, already inside because he’s a bad man.  Since the target already lives in a cell, and must by definition be a criminal, there’s neither sympathy nor concern about false accusations.  Bad people do bad things, and always more bad things than they will ever pay for.

Yesterday, Gov. Jerry Brown, who always seems to be governor in between the odd other governors of California,  signed a bill that goes a long way to prevent the jailhouse snitch from putting innocent people in prison.  The  LA Times describes it:

The new law requires prosecutors to present forensic evidence or uncompromised testimony that corroborates information provided by in-custody witnesses who claim to have been told or overheard incriminating statements by the defendant.

Dozens of Los Angeles County criminal convictions based on the testimony of jailhouse snitches have been overturned over the last quarter-century because appeals courts found the key witnesses to be  unreliable or self-serving.

The new California law, similar to Texas’ though with more specific corroboration requirements, makes a specific point about a specific problem.  The word of the jailhouse snitch, a person who has every reason to fabricate testimony that will aid him in obtaining release or some other material benefit, and no reason to concern himself with truthfulness or the harm he causes others, presents a clearcut instance of unreliable evidence.  The law is essentially the same as one passed in California in 2008, but vetoed by the interim governator because it made convicting more difficult.   Some stats make the point clearer:

This survey [PDF] from the Center for Wrongful Convictions at Northwestern Law School found that fully 48% of wrongful convictions were brought about by jailhouse testimony. The Innocence Project states that 15% of DNA exonerations were in cases of convictions that featured snitch testimony. Here’s a   Pew Trust report [PDF] on the problems with this kind of testimony.

Yet this just scratches the surface of the problem of low quality testimony.  As everyone knows, the threshold for the admissability of evidence is materiality and relevance.  The next step, most often observed in the breach, is that it be more probative than prejudicial.  It all sounds fine, but it fails to address the quality of the evidence, its reliability.  This is where things get sticky.

The best quality of evidence is an image of the perpetrator of a crime in its commission, with a posse of priests observing it coming in a close second, though the latter happens rarely except with child molestation cases.  The quality of evidence after that descends rapidly.

A peculiar phenomenon happens as the quality of evidence deteriorates.  Evidence that a judge would reject, laugh at, ridicule, when good quality evidence exists, suddenly becomes acceptable, even reliable, when no better quality evidence is available.  Come on, judge. You know exactly what I’m talking about.

It’s often slid in through the side door, rationalized as background evidence, or through the misapplication of Molineaux.  It’s explained as showing “motive” even though motive isn’t an element of the offense, and it can only bear up to scrutiny in terms of relevance by the most gymnastic of rationales.  The same evidence that is called “inconsequential, prone to abuse and of little value in showing anything more than mere coincidence” is suddenly “critical in proving that the defendant, three years before the disappearance of his wife, engaged in an angry exchange demonstrating his proclivity toward violence and animosity toward his wife.”  Same exact evidence.  Completely opposite characterization.

As California takes a giant step toward eliminating the testimony of the jailhouse snitch in an effort to prevent the uncorroborated use of evidence so unreliable, so prone to abuse, let’s not forget that it’s not the only bit of “proof” that tends to degrade the virtue of the system.  The point isn’t that people who are criminals are incapable of telling the truth, but that people who have an incentive to lie and no incentive to be truthful provide evidence that is inherently unreliable.  If it’s unreliable, it doesn’t become more reliable because there isn’t any high quality evidence available. 

From the perspective of the judge, the putative gatekeeper of unreliable evidence, the reason why this phenomenon is permitted is easy.  If the evidence is of low quality, then the defense lawyer will expose it and the jury will reject it, acquitting the defendant and being responsible for the loss to the prosecution.  Far better that the jury take the weight than the judge by refusing to permit the prosecution to make its case and putting the likely criminal back out on the street to pillage.

Except the experience is that both the defense and prosecution know the failing of low quality evidence, and each has well-rehearsed arguments to present to the jury.  The jury, on the other hand, hasn’t got a clue about low quality evidence, as most people use the ugliest of evidence to reach the most important decisions in their lives because it’s the only evidence they’ve got.  They’re instructed by the court to assess the weight of the evidence as they would in making decisions for themselves, while the reality is that people make decisions all the time based on wild speculation. If there’s any evidence at all, it’s a windfall.

That’s why so many innocent people are convicted on the uncorroborated testimony of the worst quality evidence around, the word of the jailhouse snitch.  That’s why California is right to pass a law that prohibits the conviction of a person on such uncorroborated testimony.  That’s why its a step in the right direction.  Now we need to keep walking down that path to end the phenomenon of allowing low quality, unreliable evidence just because there’s no decent evidence available.  It’s a good start. Keep going.

H/T Billy