DNA found in chewing gum leads to cracking a murder case in 1980, key accused arrested and convicted

Multnomah County District Attorney Mike Schmidt on March 18 announced that a Multnomah County judge delivered a guilty verdict for Robert Arthur Plympton, 60, for the 1980 murder of Barbara Tucker near Mt. Hood Community College in Gresham.

Incident

On January 15, 1980,  Barbara Tucker, a student at Mt. Hood Community College, was kidnapped, sexually assaulted, and beaten to death near a campus parking lot by Robert Plympton.

On the morning of January 16, 1980, students arriving for class at Mt. Hood Community College discovered the body of Tucker in a wooded area between Kane Rd and a school parking lot.

In 2000, vaginal swabs taken during Tucker’s autopsy were sent to the Oregon State Police (OSP) Crime Lab for analysis.

The Crime Lab developed a DNA profile from the swabs.

Chewing Gum and DNA

"In 2021, a genealogist with Parabon Nanolabs identified Robert Plympton as a likely contributor to the unknown DNA profile developed in 2000," read a statement issued by the Multnomah County District Attorney’s Office.

Detectives with the Gresham Police Department found Plympton living in Troutdale and began conducting surveillance.

"When they saw Plympton spit a piece of chewing gum onto the ground, detectives collected the gum and submitted it to the OSP Crime Lab," the statement said.

The lab determined the DNA profile developed from the chewing gum matched the DNA profile developed from Tucker’s vaginal swabs.

On June 8, 2021, Plympton was taken into custody and lodged at the Multnomah County Detention Center.

Bench Trial

Chief Deputy District Attorney Kirsten Snowden and Senior Deputy District Attorney Todd Jackson represented the state at trial, which took place in front of Judge Amy Baggio from February 26 to March 15, 2024.

Judge Baggio delivered her verdict on March 15 finding Plympton guilty of one count of Murder in the First Degree, and four counts of different theories of Murder in the Second Degree.

Sentencing has been scheduled for June 21 in front of Judge Baggio.

Plympton remains in custody in Multnomah County.