It seems like nearly everybody knows something about DNA. What they don't learn in high school science classes, they learn from the media and popular television crime dramas, and the knowledge they walk away with seems to always echo the same sentiment: DNA is infallible.
While bite mark evidence, hair analysis, fingerprint analysis and even eyewitness testimony have all come under fire in recent years and become more doubtful with each new study into their reliability, DNA evidence has stood strong. For many jurors, the presence of DNA evidence is linked to irrefutable guilt.
But just how reliable is DNA anyhow? New investigations into the processes of collecting, storing, testing and analyzing the evidence is gradually dismantling the bullet-proof armor that DNA evidence has had in courtrooms up to this point.
For example, the Texas Forensic Science Commission recently concluded that labs were using an outdated protocol for calculating the probability of DNA matches when a crime scene sample contained a mixture of DNA from more than one person. The change in protocol had the potential of taking what looked like a match with a certainty of more than one million to one down to something like thirty or forty to one.
This is leading to more cases like that of a Texas man who is appealing his 2014 conviction and potential death sentence in the sexual assault and strangulation death of an elderly woman in her own home back in 1980.
The convicted man's lawyer says that the DNA evidence used at trial was false. Further, it's alleged that the trail counsel didn't seek independent analysis of either the DNA evidence or the latent fingerprints found on the scene. Preliminary reviews of the evidence used to convict the defendant were questionable enough to convince a state court judge to authorize the funding to get an independent DNA and fingerprint analysis done.
Experts in the filed indicate that more challenges are likely to be faced ahead, and that neither lawyers nor jurors should put their absolute faith in DNA evidence. They stress that even DNA testing has areas of subjectivity. There's also a lot of room for mistakes to be made during the collection, transfer and storage of DNA material.
If you're being threatened with a criminal conviction based on DNA evidence, it's wise to seek out the advice of an attorney before you consider any other possible actions.
Source: MyStatesman, "DNA evidence to be analyzed again in death penalty case appeal," Claire Osborn, Jan. 15, 2017