The Shortcomings of Limited Science
Posted: January 26, 2009 2:03 pm
The Nebraska Pardons Board is hearing testimony today in the case of the “Beatrice Six” – three men and three women who were convicted of a murder committed by another man. Joseph White has already been completely exonerated by DNA testing, but his five co-defendants are seeking state pardons to clear their names. The Nebraska Attorney General is asking today for the state to grant their pardons and let them get on with their lives.
An article in today’s Omaha World-Herald details the case and explores how limited science and faulty analysis led authorities to ignore the real perpetrator and focus on six innocent people. Serological testing conducted in Nebraska before Joseph White’s trial was misinterpreted by analysts in the Nebraska State Patrol lab, and blood testing on a potential suspect in Oklahoma was botched or falsified by analyst Joyce Gilchrist (whose misconduct has contributed to at least four wrongful convictions).
The most common DNA profile would show up once in group of 250 billion people. Results often reach into numbers that are hard to fathom, like quadrillions or quintillions.
With serology, results are more common. If 10,000 people were in a stadium, it's possible that 10 to 100 could match one another under the older testing system.
Testing on mixed or degraded samples yielded even less definitive results.Read more about the case – and today’s pardon requests – in this report from ABC News
For this reason, defendants in nearly half of all exoneration cases nationwide — like several of the six men and women convicted in the Beatrice woman's death — were included as suspects by forensic serology but later excluded when the same materials were tested for DNA.
"In a lot of the cases, the serology testimony was scientifically valid and was accurate," said Peter Neufeld, co-founder of the Innocence Project, a New York-based group that helps win reversals of wrongful convictions. "The problem was that it wasn't sufficiently discriminating. In other words, you can't exclude most of the population."
Read the full story here. (Omaha World-Herald, 01/26/09)
Tags: Joseph White