Chewing Gum DNA Ends 44-Year Hunt for Oregon Killer

barbara tucker oregon
Barbara Tucker, who was murdered in 1980, seen in an undated courtesy photo provided June 9, 2021

Barbara Mae Tucker, then 19, was a regular student attending Mount Hood Community College in Gresham until on January 15, 1980 the unthinkable happened. Her body was found by another student near the school parking lot, and it was discovered she had been murdered after being kidnapped and sexually assaulted. The killer was never found and Tucker became one of scores of cold case files—until now.

At the time of the murder, investigators took DNA swabs from the victim, but it wasn’t until 20 years later in 2000 that these samples were sent to the Oregon State Police Crime Lab. Here they sat for another 20 years where in 2021, under a new grant from the National Institute of Justice, Parabon Nanolabs was able to link a suspect to the DNA samples. The man they found was Robert Plympton, now 60, who was living in nearby Troutdale.

At this time, Multnomah County Police started following Plympton in hopes of gathering conclusive DNA evidence that could connect him to the 1980 murder. One day, an investigator saw Plympton spit out a piece of chewing gum on the sidewalk and knew this was the evidence they’d been waiting for. The investigator quickly retrieved the gum and sent it to the lab so a genealogist could compare the two samples—lo and behold, it was a match.

Plympton was later arrested based on this new evidence and was eventually brought before judges on a bench trial through the Multnomah County District Attorney's Office last week. Though he pleaded not guilty, he was subsequently found guilty on one count of first degree murder and four counts of “different theories of murder in the second degree” by judge Amy Baggio last Friday, March 15. 

However, although the evidence did connect Plympton to the murder, it was not enough to conclusively convict him of rape because the prosecutors failed to prove beyond a reasonable doubt that the assault happened while Tucker was still alive. The final sentencing is scheduled for June 21 while Plympton remains in custody, but Plympton’s lawyers say they will appeal the judge’s verdict.