Flawed Forensics: Chain of Custody Errors

By Brock Benjamin
Founding Attorney

What are the grounds for challenging the chain of custody?

Forensic evidence is widely regarded as the most powerful evidence a prosecutor or defendant can introduce during a criminal trial.  America’s fascination with forensic evidence is commonly referred to as the CSI effect or CSI syndrome. After spending years watching shows like CSI, Americans have come to believe that forensic evidence is the cornerstone to any successful prosecution.  The danger arises, however, when a jury gives great credence to flawed forensic evidence. While forensics can be a powerful tool, there are certain types of evidence that should not be deemed reliable, and other forensics that must be disregarded when investigators mishandle the evidence. Criminal defendants facing potential conviction based on forensic evidence will need to understand the many possible grounds for challenging flawed forensics.

Houston Crime Lab Investigated After Mailing Mishap

As an illustration of just what can go wrong when it comes to forensics, take the situation currently being investigated regarding Houston’s Department of Public Safety crime lab.  News outlets report that the Houston crime lab accidentally mailed blood samples from a defendant awaiting trial for a felony DWI case in north Texas to a criminal defense lawyer.

The attorney who received the blood package from another attorney’s client immediately requested an investigation.  Investigations show that samples were first mailed from a lab in Garland, Texas, then sent to the Houston Lab. After testing the samples, rather than return them to the sender, they were mailed to the random Houston attorney.  The chain of custody for the case has now been entirely destroyed and defense attorneys are calling for dismissal of the case.

Chain of Custody Problems

The chain of custody for any piece of evidence that the prosecutor seeks to introduce must be unbroken.  It is crucial that the prosecutor prove that the item proffered into evidence is what it purports to be, and this requires evidence of who had possession of the item from the time of its seizure through its introduction at trial.  A break in the chain opens the potential for evidence mishandling. A defense attorney can challenge the prosecution’s chain of custody and potentially have evidence excluded if the chain has been broken. Chain of custody arguments are complex and anyone facing criminal charges who believes the evidence was not correctly gathered, tested, and stored should contact a criminal defense attorney right away.

About the Author
Brock Benjamin is board-certified in Criminal Law by the Texas Board of Legal Specialization.  His practice is primarily state and federal criminal law and appeals.Brock 

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