Evidence retention failures thwart pursuit of innocence claims

On Tuesday, Texas witnessed its 34th DNA-based exoneration since 2001, this time again from Dallas County which is one of the only jurisdictions in Texas that saved old biological evidence. Such evidence only exists in about 10% of violent crime cases anyway, so DNA alone won't help most innocent offenders. But what about cases where DNA evidence existed but wasn't preserved?

USA Today this week published a pair of interesting stories focused on an issue made more immediate by the large number of recent DNA-based exonerations around the country - the failure of many jurisdictions to preserve DNA evidence ("DNA not saved in half of states," Aug. 6):

Evidence preservation has been the key to freeing more than 200 wrongfully convicted prisoners, says the Innocence Project, a group that works to free the innocent based on DNA testing.

Preserving DNA also has helped secure convictions. "We're becoming more successful in identifying perpetrators in cold cases than we were when we didn't have this technology," says Scott Storey, district attorney in Jefferson County, Colo.

The USA Today piece lists Texas as among states that retain biological evidence, but that's a) relatively new and b) inconsistently applied. District clerks control such evidence in Texas post-conviction, and no analysis of their evidence collection and retention practices has been performed to my knowledge. Who knows how different jurisdictions are handling it? Texas does not require district clerks to keep biological evidence that wasn't admitted in court, which may result in potentially exculpatory evidence being destroyed. And in some places like Harris County, prosecutors make an end run around evidence preservation requirements by insisting on evidence destruction a condition of plea bargains.

A companion story in USA Today ("In lieu of DNA evidence, exoneration proves tougher," Aug. 6) questioned whether the relatively small number of cases with DNA might thwart efforts to prove most innocence cases post-conviction. The story quoted Jeff Blackburn of the Innocence Project of Texas (for whom, I should remind readers unaware of the possible conflict, this writer is a paid consultant):

Jeff Blackburn, chief counsel for the Innocence Project of Texas, fears Texas cases dependent on DNA could "run out" within a year. Of the 700 cases his group believes have potentially credible claims, 225 would be heavily weighted on the outcome of DNA analysis — if the material exists. The rest involve issues such as witness identification problems and coerced confessions.

Some advocates' concerns over the availability of DNA have injected tension into a movement to free the wrongfully convicted.

Barry Scheck, co-director of the Innocence Project, a national group whose work relies almost exclusively on DNA testing, says enough cases exist to sustain a decade's worth of potential exonerations. His group says the DNA caseload has increased from 141 in 2004 to 278 this year.

"These cases are not slowing down," he says, adding his colleagues "are not looking hard enough." He says DNA cases will decline eventually — but not yet.

Just because DNA cases may slow down, though, that doesn't mean false convictions will have ceased, only that their causes will have been exposed by a serendipitous case study generated by this new technology. Unscientific eyewitness ID practices, false confessions, mendacious informants, forensic errors, prosecutors withholding exculpatory evidence, and a handful of other key systemic flaws will continue to convict innocent people after old DNA cases run out if they're not addressed by the Legislature or the courts.

With proper evidence preservation going forward, perhaps some new technology we can't even imagine today will provide another window into justice system errors. Given society's recent experience with DNA proving innocence in old cases, it's worth hanging onto the evidence to find out.