DNA mixture SNAFU a mess, but don't expect 'deluge' of innocence claims

An otherwise well-done Fort Worth Star-Telegram story on the Texas Court of Criminal Appeals races opened with this comment: "The Texas Court of Criminal Appeals is about to get hit by a deluge of post-conviction claims that 'junk' science was used to convict the innocent. It could hear as many as 50,000 post-conviction cases involving the improper handling of 'mixed DNA' alone."

For the record, Grits thinks that assessment dramatically overstates matters. Yes, it's possible there are as many as 50,000 cases involving DNA mixtures statewide. But the likelihood that all will result in habeas writs, much less that those writs would ever make it past the trial-court level to the CCA, is another matter entirely.

Over the next few months we'll begin to see re-evaluations of DNA mixture analyses and learn what proportion of those 50,000 cases may have been so far off as to constitute grounds for relief. But the number will almost certainly be much, much lower than 50K. And even where bad science was used to secure a conviction, there may be other evidence against a defendant which the CCA could decide still holds up.

Similarly, reviews of bite-mark and hair-and-fiber cases involve hundreds and thousands of cases, respectively, but a much smaller number will evince errors in expert testimony so significant that a defendant may realistically expect relief. Typically bite-mark or hair microscopy were not the sole evidence used to accuse a defendant.

We're all guessing right now. No one can know for sure and I reserve the right to adjust this guesstimate based on new information. But if the number of successful habeas writs over DNA-mixture claims rises to several hundred, the process will have exceeded your correspondent's expectations. There will be some, but others surely will fall through the cracks. And, of course, in many cases re-evaluating DNA-mixture calculations won't affect the outcome at all.

For these reasons, Grits sees little evidence yet that the creation of Texas' junk science writ and the state's reviews of flawed forensics at the Forensic Science Commission will lead to vast numbers of post-conviction innocence claims. There remains significant uncertainty surrounding the process, but the fact that we don't know the outcome yet doesn't justify speculating the most exorbitant estimates.

Read more here: http://www.star-telegram.com/news/politics-government/article61513892.html?utm_source=WhatCountsEmail&utm_medium=newsmail_premium_texastake&utm_campaign=newsmail_Texas%20Take%20Newsletter#storylink=cpy"