Advancements in the science of criminal investigation--particularly genetic data--offer the comforting notion that courts and law enforcement are becoming more objective and less error prone. But just how damning is DNA evidence?
A series in the Los Angeles Times questions a law enforcement tool that many take for granted as being in our best interest. The drama started when a probe of a government database by an Arizona crime lab analyst turned up a remarkable number of DNA matches. The revelation cast doubt on the presumption that genetic evidence is an unassailable smoking gun.
The FBI and state officials have tried to dismiss the findings, alleging that the statistics and methodology used are misleading. But advocates for the accused argue that it is in fact the government that is manipulating DNA evidence, by misrepresenting the odds of a coincidental match and potentially swaying jurors in the wrong direction.
"For years, DNA's strength in the courtroom has been the brute power of its numbers. It's hard to argue with odds like 1 in 100 billion."At first blush, the Arizona matches appeared to contradict those statistics and the popular notion that DNA profiles, like DNA, were essentially unique....
"Bruce Weir, a statistician at the University of Washington who has studied the issue, said these assumptions should be tested empirically in the national database system.
" 'Instead of saying we predict there will be a match, let's open it up and look,' Weir said."
Over the years, concerns about flawed DNA evidence have surfaced in real crime cases, calling into question how much faith society should invest in DNA when people's lives hang in the balance.
It's tempting to embrace science as an antidote to the arbitrariness that pervades our courts and law enforcement institutions, especially now that technology has evolved to the point that we can all be reduced our most basic genetic elements. But the system may never escape its inborn deficiencies: to err is human.