Commander Rob Lamoureux speaks about his experience working on Jennifer Brinkman homicide case on Tuesday, Nov. 29, 2022 in Marysville, Washington. (Olivia Vanni / The Herald)

Commander Rob Lamoureux speaks about his experience working on Jennifer Brinkman homicide case on Tuesday, Nov. 29, 2022 in Marysville, Washington. (Olivia Vanni / The Herald)

Suspect arrested in 1998 cold case homicide of Marysville woman, 19

Jennifer Brinkman was found dead in her Marysville home with axe wounds over 20 years ago. Her suspected killer, 52, is a Renton man.

MARYSVILLE — In her 19 years of life, Jennifer Brinkman was known in the Marysville community as somebody eager to make friends. She frequented the local library.

The young woman was found dead in her bedroom in 1998. It would be 24 years before police identified a suspect in her violent killing.

On Monday, Marysville detectives arrested a 52-year-old man at his workplace in Renton for investigation of first-degree murder in the cold case killing of Brinkman, then 19.

Police did not publicly identify the suspect at a press conference Tuesday, pointing to steps in the judicial process that had yet to happen.

On March 13, 1998, Brinkman’s father and his girlfriend left for a trip to Disneyland they had planned. Brinkman opted to stay behind. Before leaving on the trip, the father went shopping and bought food, drinks and cigarettes to last his daughter until he got home.

When the pair returned home eight days later on March 21, they found Brinkman’s body in her bedroom inside the home in the 1900 block of Grove Street. Brinkman had suffered axe wounds to her neck and body. Evidence collected at the crime scene suggested there was a struggle before Brinkman was killed, police wrote.

A bloody axe with a wooden handle was found near the bed, police wrote. The father reported he was “certain” the axe was in the garage when he left on his trip.

There was no evidence of forced entry at the scene of the crime, police wrote. Evidence suggested Brinkman had likely been dead for several days prior to the discovery of her body.

Police collected evidence and canvassed the area. Leads ran cold.

Brinkman spent a lot of time walking around Marysville, particularly in the area from her house to State Avenue and to the library.

“She was extremely friendly and would easily strike up a conversation with strangers,” police said.

Brinkman also spent time on telephone dating and chat lines as well as library computers. She had been looking for a romantic partner, police said, based on witness statements and journal entries collected from Brinkman’s room.

Investigators believe Brinkman met the suspect through a chat line.

Two weeks before Brinkman was killed, evidence suggests the suspect made plans to meet her.

Detectives found a letter dated March 10, 1998, addressed to Brinkman with a return address at the suspect’s Bellevue home.

“Dear Jenn,” the letter reads. “I hope your week has gone good. Are you and your parents getting along better? Please try and get along with your mother, so we can at least see each other on a regular basis. … I miss you so much. I have your address, I should just drive over and spend the day with you. How does that sound?”

In a 1998 interview, Brinkman’s mother told authorities her daughter had made plans to meet a man “from the chat lines” for a date at the movies, police wrote.

Based on that information, detectives tried to contact the suspect. He denied ever knowing or having met Brinkman.

A DNA sample was collected from the letter written by the suspect. Detectives also collected a DNA sample from Brinkman’s fingernails.

At the time of the homicide, “DNA technology did not exist that was capable of identifying and profiling that DNA sample to what we could use in an evidentiary manner,” Marysville Detective Wade Rediger said.

Over two decades later, the DNA samples were sent to Parabon NanoLabs in Virginia. The private lab uploaded a genetic profile to the ancestry website GEDMatch, and a genealogist built a family tree for the suspect. That research pointed detectives to the suspect.

On Nov. 16, detectives tried to call multiple numbers associated with the suspect. There was no answer. A few days later, they tracked him down in Redmond.

When police detained the suspect, he reportedly denied meeting Brinkman at first.

Then he said, “We may have crossed lines in the chat lines. But I, like that particular face? I’ve never met that…”

Investigators served a search warrant to collect the suspect’s DNA and sent it to a state forensics lab.

Washington State Patrol lab reports indicated there was “very strong support” that the suspect’s DNA was a contributor to DNA evidence collected from the victim’s body as well as the envelope mailed from the suspect’s address.

The original lead detective on the case was Robb Lamoureux of Marysville Police Department. He attended Tuesday’s press conference.

“It’s hard to put into words,” Cmdr. Lamoureux said. “We’ve got a conclusion to this. We’re finally able to put it on a shelf and have some closure …”

Brinkman’s homicide was the only cold case Marysville police had left to crack, officer TJ San Miguel told The Daily Herald.

The suspect remained in custody Tuesday at the Snohomish County Jail.

Lamoureux said Brinkman’s mother was “extremely emotional” upon hearing a suspect had been arrested in her daughter’s cold case.

“She cried and was very thankful for the work that we put into it,” Lamoureux said. “So I think it was probably an overwhelming emotion for her.”

Brinkman’s father died in 2013, Lamoureux said.

“We weren’t able to provide him that closure before he passed away,” Lamoureux said. “But we’re very thankful that we were able to come to a resolution with her mom.”

Ellen Dennis: 425-339-3486; ellen.dennis@heraldnet.com; Twitter: @reporterellen.

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