Is forensic evidence really reliable?

From FBI hair-matching programs to evidence tampering at crime labs, sometimes forensic evidence isn’t as reliable as it first appears

Everyone has seen at least a few minutes of forensic crime shows on television. In these procedurals, scientists working in a space-age facility can solve crimes by a single footprint, lock of hair, or other minute detail, fact, or sample taken from the crime scene. Examination leads to solid evidence, which then leads to a confession. Case closed.

In real life, nothing is so certain.

Crime scene investigation labs are often overworked and understaffed. Expert testimony can contradict evidence used by the prosecution. And in some cases, the underlying forensic methods used to try to obtain a conviction can be shown to be false or unreliable.

FBI used unreliable forensic hair matching for decades

Recently the FBI came under fire for false evidence given in hundreds of cases spanning decades over forensic hair matching taken from crime scenes.

As reported recently by the Washington Post, efforts by the National Association of Criminal Defense Lawyers and the Innocence Project revealed FBI testimony overstated forensic matches to favor the prosecution in thousands of cases prior to 2000. NACDL executive director Norman Reimer said in an interview with Associations Now that FBI witnesses for the prosecution "wouldn't just simply say that there was a microscopic similarity" between two hairs, but "say it was a 100 percent match." This misled jurors into thinking rock-solid forensic evidence existed in the case, when in fact the findings could easily have been thrown into doubt. After all, many people have similar hair types. Even similarity between two hair samples wasn't always apparent, however. In one case in which this type of forensic "evidence" was used, an FBI agent testified that hair found from a dog at the crime scene matched the defendant's hair type.

Alarmingly, many of the cases in question resulted in convictions, including some cases involving the death penalty. It isn't just federal cases that were affected, either. Many states trained by the FBI used a similar method, meaning that many convictions can now be thrown into doubt at both the federal and state level.

Contesting evidence at trial

The investigation into forensic hair matching shows how important it is to contest evidence in a criminal case, even evidence obtained "scientifically." Certain alcohol breath-testing devices have been shown to be unreliable, for example. In Massachusetts, the state's highest court on April 8 called for an increased investigation into a former chemist at a state-run crime lab who has admitted to tampering with drug evidence.

These are just a few examples of situations in which forensic evidence has been called into question. If you have been charged with a crime, the prosecution will use all possible evidence against you. That is why it is important to protect yourself and your rights throughout criminal proceedings.

At DeVito & Visconti, PA, John DeVito provides vigorous defense against a variety of criminal charges. Contact John E. DeVito, Esq., to discuss your particular situation and potential defenses.

Keywords: forensic evidence, evidence tampering, unreliable witness, criminal defense.