Can challenges be raised against DNA evidence?

Although DNA evidence may be characterized as irrefutable proof in television and movie dramatizations, real life applications raise some concerns.

Specifically, there are variables that can affect the reliability of DNA evidence. One of the biggest problems with DNA samples is contamination, resulting in tainted evidence. DNA evidence must be properly collected, processed with care at the forensics lab, and safely stored and transported to avoid contamination at any point in the chain of custody.

In a recent example, authorities claim that they discovered a 34-year-old male defendant’s DNA on multiple objects at the crime site. The defendant is accused of several crimes, including homicide, burglary and arson. However, that evidentiary announcement came 17 months after the suspect had been arrested. The defendant’s attorney requested a comparable amount of time to analyze the DNA, but the court has not yet set a timetable.

As a criminal defense law firm, our attorneys appreciate the time and work involved in preparing a strong defense to felony charges. When DNA evidence is suddenly discovered after months of investigation, our attorneys may have some pointed questions to ask about the chain of evidentiary custody.

The defense is entitled to know how DNA evidence was identified and collected, how it was analyzed and stored, and how the sample was transported between facilities. If DNA evidence was collected months after an alleged incident, the defense may look for potential contamination.

An attorney can also fight to protect a criminal defendant’s procedural rights. In this example, that may require requesting relief from the court, such as an extension to respond to newly produced evidence. The defense may also require the court’s assistance in obtaining relevant evidence in the prosecutor’s possession.  

Source: Washington Post, “Additional DNA evidence links suspect to D.C. quadruple slaying, prosecutors say,” Keith L. Alexander, Oct. 28, 2016