DNA collected from chewing gum leads to arrest, conviction in unsolved 1980s murder

(CNN) — DNA found on a discarded piece of gum led to the arrest and conviction of a suspect in a 1980 cold case murder in Oregon, prosecutors said.

Robert Plimpton, 60, was convicted last week of one count of first-degree murder and four counts of second-degree murder in the slaying of Mount Hood Community College student Barbara Tucker, a statement from the office said. Multnomah County District Attorney’s Office.

According to the statement, 19-year-old Tucker was “abducted, sexually assaulted and beaten” on January 15, 1980. Rape and sexual assault charges against Plimpton were dropped, according to a document released by the district attorney’s office.

Plimpton has pleaded not guilty and his lawyers say they intend to appeal his sentence. “We will appeal and are confident that their convictions will be overturned,” attorneys Stephen House and Jacob House said in a statement to CNN.

Plimpton remains in custody in Multnomah County awaiting sentencing, the district attorney’s office said. His sentencing hearing is scheduled for June.

A witness heard screams

Barbara Tucker, murdered in 1980 (Tucker Family/Gresham Police Department)

Witnesses saw a woman in apparent distress at the time of the murder, documents from the district attorney’s office indicate. One woman described seeing a woman “waving her hands with a bloody face,” while another said she saw a man “looking into the bushes next to the (university) parking lot.”

One man said he heard a woman scream and saw two figures in the distance, and a fourth witness reported seeing a woman with mud on her pants, waving her hands on the side of the road.
Tucker’s body was found the next morning near a parking lot by students on their way to classes at the university in Gresham, the district attorney’s news release states.

“These cold cases have not been lost or forgotten to our department,” then-Police Chief Claudio Grandjean said in a statement after Plimpton’s arrest in June 2021.

“Each person represents an individual to our officers, and their tragic stories are passed down from generation to generation in the hope that one day their names will be honored and justice will be experienced and their cases will be closed,” he added.

According to a district attorney’s press release, swabs taken during Tucker’s autopsy were used to create a DNA profile of the suspect.

The investigation took a turn after police asked Parabon Nanolabs, a Virginia-based DNA technology company, to examine the profiles and try to identify possible matches.

“Instant phenotype prediction,” or a test to predict a person’s physical traits based on their DNA, helps genetic genealogists identify potential suspects, which, according to CC Moore, Parabon’s head of genetic genealogy, “”was key. This case.”

Moore said that while he was constructing family trees of people who shared DNA with samples provided by police, he discovered World War II registration cards of men with red hair.

“This case was the most confident prediction about red hair that Parabon scientists had at the time,” Moore told CNN. “Therefore, there was an extremely high probability that the person who murdered and raped Barbara was a redhead.”

“It helped me because it made me focus on a particular family line and follow that red hair. And then I landed in Oregon.”

The suspect was placed under surveillance

In March 2021, Moore was able to identify Robert Plimpton as a possible suspect, he said.

Investigators used that information to begin surveillance of Plimpton and were able to collect a piece of gum that detectives saw at the moment he spit it out, the district attorney’s office said. DNA extracted from the gum matched the profile of the autopsy swabs, and Plimpton was arrested on June 8, 2021.

“I felt completely taken aback. It was unbelievable,” Tucker’s sister, Susan Petter, told CNN affiliate KATU in an interview at the time. “It was really good news. “I gave up,” said Pater.

Moore called the case “one of the highlights of my career in genetic genealogy.”

“We will never give anyone a happy ending,” he said. “I am very fortunate to be able to help families and survivors of violent crimes. “It’s incredibly meaningful.”