It’s been some time since I’ve posted a new blog. What can I say—life gets in the way! It’s amazing how getting into and out of the habit of writing can happen so easily. I’ve decided to get back into the habit of writing and that begins with this blog.

I’ve written before here and here about the pluses and minuses of using DNA evidence as the life-blood of securing convictions in today’s criminal justice system. However, I had a real eye-opener the other day while talking to a lawyer friend about the plot for a book I was contemplating.

The plot will make use of unidentifiable DNA (that is, DNA not yet entered into any database system for a match), and the lawyer told me about a couple of cases where the DNA evidence actually pointed to the wrong perpetrator and would have convicted the wrong person of the crimes if further evidence were not available.

The Academy of Forensic Sciences in 2009 admitted that the use of forensics is as much an art as a science and that the science may not always be definitive.

For decades, the criminal justice system relied on DNA evidence as rock solid and foolproof to achieve convictions. DNA was considered the gold standard for identifying criminals.However, the couple of cases my lawyer friend told me about convinced me that there is more to criminal detection than simply matching DNA evidence.

Take the example of a homeless man’s DNA being found on a wealthy murder victim who was killed in his mansion. The homeless man was documented to have been hospitalized at the time of the murder and could not possibly have committed the crime, nor was there any evidence that the homeless man had ever been to that victim’s home.

Extensive and clever investigation (the art part of forensics) finally found the link.The homeless man had been treated by a paramedic earlier in the day and the paramedic had transported the homeless man to the hospital. That same paramedic was called to the scene of the wealthy man’s attack and, upon examination, declared the person dead. It was later determined that the paramedic had not changed his gloves after the callout for the homeless man and contaminated the wealthy victim’s body with the homeless man’s DNA—as transfer from the unchanged glove of the paramedic.

This friend told me of another case in which a plumber was arrested on a rape charge when his DNA was found on the underwear of the victim. It was later determined that the plumber had worked on plumbing in that same closet the week before the rape occurred in that same enclosed area. The plumber’s DNA had transferred to the surfaces of the closet and also to the rape victim’s underwear.

My imagination can come up with other instances where DNA could innocently transfer from one person to another, either directly or on a surface for later transfer; and this is how innocent people can be wrongly convicted of a crime with supposedly irrefutable DNA evidence.

Something as innocent as brushing up against a potential criminal and having your sweat transfer onto the person before he or she commits a sinister deed could be enough to link you to a crime you did not commit by transferred DNA.

As a writer, this puts my imagination on overload and gives me several ideas for use of such innocent DNA transfer in my next murder mystery.

Thoughts? Comments? I’d love to hear them!