PEORIA — Police say DNA was the key that led to the arrest of a Eureka man and the solving of a 32-year-old slaying of a Tacoma, Wash., girl.

At a news conference Monday afternoon, Tacoma Police Chief Donald Ramsdell said Robert Washburn had been approached in March 2017 to provide a voluntary sample of his DNA, which was then sent to a private lab.

"On May 7, 2018, the lab notified of a match," he said. Three days later, Tacoma police officers, assisted by the FBI, the Illinois State Police and members of the Woodford County Sheriff's Office arrested Washburn at his apartment in the Woodridge Apartment Complex.

Jennifer Bastian, 13, disappeared in August 1986 while riding her bike. Her body was found in a wooded area of the park 24 days after she vanished. She had been sexually assaulted and strangled. The case changed how Tacoma parents watched and raised their children.

Bastian's family praised the work by police and expressed relief and thanks that justice could be served for the girl.

Washburn, who was charged by a bench warrant from the state of Washington with murder in the first degree, remains in the Woodford County Jail in Eureka, having waived the right to an extradition hearing at a brief hearing Friday morning.  Mark Lindquist, the prosecuting attorney in Pierce County, where Tacoma is located, said he expects Washburn to be returned to the state of Washington by May 21 "give or take a day or two."

Washburn used to live in the Tacoma area. He was identified after the Tacoma police's cold case unit, which was formed in 2011 with the help of a grant, did additional work on the case. Male DNA was found in the girl's swimsuit and run through existing databases at the time without a match. Later, the cold case unit, along with the FBI, developed a list of more than 100 people from whom it sought to obtain voluntary samples of DNA.

A head agent with the Tacoma area FBI unit said he didn't have details on how Washburn was approached. He reiterated, as the others, that Washburn voluntarily gave a DNA sample.

Washburn, officials have said, was first listed as a suspect back in 1986 when he called in a tip about the similar slaying of 12-year-old Michella Welch in the same park where Bastian was found. Washburn also said he had been in the park when Bastian was still missing. He told police at the time he would jog in the park as often as twice a day. For a long time, police believed the two girls had been killed by the same person. DNA has since proved that not to be the case.

Andy Kravetz can be reached at 686-3283 or Follow him on Twitter @andykravetz.