Authorities in Washington announced they have identified a murder suspect in the 32-year-old murder of a teenage girl.

Michelle Koski, 17, vanished from her Seattle Lake City neighborhood on Aug. 18, 1990, according to Fox Seattle affiliate KCPQ. She reportedly visited a Seattle apartment earlier that day, but investigators believed Koski left to meet someone else for a drink later on.

“The person probably intended to have sex, and she didn’t want to,” Snohomish County Detective Jim Scharf told the outlet in 2012. “She probably tried to flee, and he ran her down and strangled her.”

A week later, a woman walking her dog near Echo Lake Road and Highway 522 in Snohomish — 15 miles from where the teen went missing — came upon Koski’s body. Investigators said that whoever committed the crime used pieces of concrete from a nearby pile to “finish her off.”

Koski’s murder went unsolved for three decades until officials with the Snohomish County Sheriff’s Office announced Thursday that they had identified the suspect as Robert A. Brooks, using the latest advancements in genetic genealogy.

“After more than 30 years of searching for answers following this terrible murder, we can finally provide Michelle’s family with some answers,” said Snohomish Sheriff Adam Fortney. “Thanks to the relentless persistence of our cold case detectives, new DNA technology, and advancements in genetic genealogy, we are now able to solve cases we once thought we’d never find the answers to.”

Authorities say Robert Brooks — who was 22 at the time and had just been released from prison, according to Seattle news station KOMO — was living with a relative only a few blocks from Koski. Authorities did not say for what he was previously convicted, though KOMO reported that he’d been convicted as a juvenile.

Brooks died of natural causes at age 48 in King County, Washington, on Oct. 26, 2016.