In the end, it was a discarded piece of chewing gum, casually spit on the ground in 2021, that was the key to solving the cold-case murder of a college student that had confounded the authorities in Oregon for more than four decades. Robert Arthur Plympton had been under police surveillance since the authorities determined that year that he was a “likely contributor” to a DNA profile developed from swabs taken from the body of Barbara Mae Tucker, who was 19 when she was murdered on the Mount Hood Community College campus in 1980. On Friday, Plympton, 60, was found guilty of murdering Tucker after a three-week bench trial in Portland, Oregon, the New York Times reports. According to The Oregonian, which reported on the investigation and Mr. Plympton’s conviction, it was the oldest cold-case homicide in Gresham, Ore., east of Portland.
.When investigators saw Plympton spit a piece of chewing gum onto the ground, they collected it and submitted it to a state police crime lab, prosecutors said. “The lab determined the DNA profile developed from the chewing gum matched the DNA profile developed from Tucker’s vaginal swabs,” the district attorney’s office said. Plympton was arrested on June 8, 2021, as he was driving away from the Troutdale home he shared with his wife and son, The Oregonian reported. He had a criminal record, including a conviction for second-degree kidnapping in Multnomah County in 1985, according to the Oregon Department of Corrections. Judge Amy Baggio of Multnomah County Circuit Court found Plympton guilty of one count of first-degree murder, and four counts of “different theories of murder in the second degree,” according to the district attorney’s office. “To be clear, this court has zero doubt whatsoever that Robert Plympton beat Barbara Tucker in her head and face until she died,” she said at the trial. “He did.” Plympton is scheduled to be sentenced on June 21, he faces a life sentence with the possibility of parole after 30 years on the first-degree murder charge.