Plant DNA May Help Track Down Criminals

Plant DNA May Help Track Down Criminals


Criminals, beware: That pollen on your jacket could place you at the crime scene. While far less well-known than fingerprints, handwriting and ballistics, forensic botany has been a part of crime fighting since 1935. In a New Jersey court that year, Arthur Koehler of the U.S. Forest Service, an expert in wood anatomy and identification, gave expert testimony that brought justice for the famous parents of the Lindbergh baby. Koehler testified that part of the wooden ladder used to abduct 20-month-old Charles from a second-story bedroom matched wood from a floorboard in Bruno Richard Hauptmann’s attic—evidence that led to the defendant’s conviction and eventual sentence of death by electrocution.

Although the admission of Koehler’s testimony in trial was hotly debated, since then the use of plant remains has come to be widely accepted as reliable scientific evidence within the criminal justice system. Now a research team led by David Gangitano of Sam Houston State University’s Department of Forensic Science has discovered new applications for forensic botany. One study, published in the International Journal of Legal Medicine on February 29, shows the potential of marijuana DNA to help solve related drug trafficking offenses, and another shows how pollen DNA can aid forensic investigations.

Now that marijuana is legal for medical use in 23 states and for recreational use in four others, law enforcement faces the unique challenge of blocking its entry to the states where it is still illegal. The tools currently available to law enforcement for identifying marijuana are sufficient to prosecute those in possession of the drug, but they won’t help police trace the plants back to where and who they came from. The Sam Houston research team used a method of DNA analysis that they believe could help law enforcement identify marijuana in cases where it enters the U.S. illegally and even link separate cases of marijuana trafficking to a single distributor.