DNA evidence is well-validated. But if you think DNA is the perfect evidence to present at trial, think again. It may not be.
Yes, DNA evidence is scientifically based and can be presented in court under certain circumstances.
But as Forensic’s Blog points out, two issues may derail the use of DNA and other forensic evidence.
Chain of Custody
What is the “chain of custody”?
It is the DOCUMENTED trail of every person who accessed (“touched, moved, or stored”) a piece of evidence. The documentation is chronological and ideally logged in real time, not hours after the fact.
What could go wrong?
Let’s say that at 1:23 pm, Diana placed a piece of evidence in a locker and locked the locker. Then at 3:53 pm, Denis went to the locker, which was unlocked, and removed the evidence from the locker. Defense attorneys will have a field day with that, and may pressure the judge to state that the evidence is inadmissible because of possible tampering by an unidentified person.
Cross-Contamination
Closely related to the chain of custody is the possibility of cross-contamination. In the case of DNA, this happens when DNA from a crime scene is mixed with another person’s DNA.
I’ve told the story of the mystery female criminal whose DNA was found at crime scenes in three different countries over a decade. The only problem was that the woman’s DNA was found on the burned body of a MAN. Eventually the authorities figured out that the woman worked in a packing center specializing in medical supplies…and that her DNA had contaminated the medical supplies and ended up in the crime scene samples.
How to Minimize Errors
Forensic’s Blog suggests several ways to avoid chain of custody issues and cross-contamination. These include established and enforced procedures for handling, packaging, and labeling data; separating tasks; and establishing zones of exclusion at crime scenes.
In addition to establishment and enforcement, education is essential. (Sorrye.) Not only for the forensic professionals gathering the evidence, but for everyone who deals with the evidence…including biometric vendors and their customers.
If you need assistance in creating educational content for proper evidence handling, Bredemarket can help. Talk to me.
Bredemarket 