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Can DNA evidence be challenged?

On Behalf of | Sep 12, 2022 | Criminal Defense

You’ve been accused of a violent crime, like murder, and the police say that you might as well confess – they found your genetic evidence at the crime scene. “DNA doesn’t lie,” they tell you.

Or, does it? DNA evidence has become a sort of gold standard when it comes to forensic evidence, and juries and judges do tend to trust it. But that does not mean that DNA evidence (or the forensic analysis that goes with it) is utterly infallible. 

How to challenge genetic evidence in court

Even the American Bar Association has urged caution when it comes to portraying DNA evidence as utterly “conclusive” in courtrooms. At best, DNA can give a “likely” match to a specific individual, but it’s not absolute. 

Because it now takes so little genetic material to produce test results, the capacity for mistakes can be huge. Trace amounts of genetic material can be transferred very easily between objects and people, and that can lead to huge problems. For example:

  • A partial DNA match could have thousands of matches out there among a defendant’s distant relatives.
  • An uncleaned testing device or slide could be accidentally reused in a lab, leading to false results.
  • Genetic material could have been deposited at a crime scene days, weeks or months prior to a violent crime – and there’s no way to determine when it was left.
  • The DNA analyst could be secretly influenced by members of law enforcement or their own biases to produce “definitive” results.
  • A poorly-trained analyst could simply misinterpret the results of genetic testing and draw incorrect conclusions.

If you’ve been charged with murder or another violent crime based on genetic evidence, don’t assume that you’re case is closed. An educated defense can overcome many things.