EVERETT — More than 20 years after an Arlington man was convicted of murder, a jury found him guilty in the 2024 killing of a woman near Lake Stevens.

On Aug. 20, 2024, a man was mowing his neighbor’s property in Lake Stevens when he was struck by a strong odor: death. Under some brush, he discovered the nude body of Katie McQueen, 37, of Mariposa, California, according to court documents.

Upon arrival, investigators found footprints in the area and evidence of attempts to conceal the body with brush, court documents said.

Due to the level of decomposition, the Snohomish County Medical Examiner’s Office struggled to determine how McQueen died, but examiners noted significant trauma to her neck, court documents said.

On Nov. 5, 2024, the Washington State Patrol’s crime lab was able to match DNA from a swab of McQueen’s right wrist to Mark Downey, 58, court documents said.

Downey, a registered sex offender, was living in group housing for sex offenders on Smokey Point Boulevard at the time. In November 2022, a judge sentenced Downey to two years in prison after he pleaded guilty to molesting a girl in Mountlake Terrace.

In 2005, Downey pleaded guilty to second-degree murder for the killing of Kathy Lynn Erickson, 35, in Bellingham. A Whatcom County judge sentenced him to nearly 18 years in prison. He also has a previous felony sex crime conviction from 1998 in Nebraska.

In mid-September 2024, during a routine probation check, the house manager had told police that Downey no longer lived there. He said Downey had left about three weeks earlier, en route to Arizona or Mexico.

Investigators discovered that Downey was in custody in Arizona after authorities transferred him following an arrest on Aug. 25, 2024, in Mexico, court documents said. In late November 2024, he was transferred to the Snohomish County Jail.

In an interview with law enforcement, Downey said he went to Mexico for a medical procedure, court documents said. When investigators showed him pictures of McQueen, he denied knowing her or having any contact with any women, saying he believed it would be a violation of his probation.

Later, Downey changed his story multiple times, according to police.

In one version, McQueen and a man approached him near a bus stop, and she reportedly started kissing him, court documents said. He told investigators he kissed her wrist and breast before panicking and leaving.

In another version, he gave McQueen and the man a ride, dropping the pair off at a gas station, court documents said. Then the story evolved to be that he witnessed the man stab McQueen in the throat with a knife, according to documents.

He told detectives he fled to Mexico out of fear he would be “blamed as an accessory to the murder,” court documents said.

Investigators confronted Downey about the inconsistencies in his stories and asked if the interaction with McQueen “got heated,” court documents said. Downey reportedly replied that there was no self-defense law in the state. When investigators told him there was, he claimed she attacked him.

Downey told investigators she had solicited sex from him for $20, court documents said. When he told her he was a registered sex offender, she reportedly punched him in the nose. He then reported she attacked him with a knife, but he used his black belt in martial arts to make her stab herself in the throat.

Eventually, he acknowledged killing McQueen, court documents said. He told investigators she wanted to have sex on the hood of his car, but laughed at him when he couldn’t get aroused. This hurt his feelings, so he stabbed her in the throat, took her clothing to throw away at a Safeway in Arlington and fled to Mexico the next morning, he reportedly said.

Prosecutors charged Downey with second-degree murder, court documents said. After an 11-day trial, a jury found him guilty of second-degree murder with a deadly weapon special verdict on April 8 in the Snohomish County Superior Court.

His sentencing is scheduled for June 4 before Superior Court Judge Richard Okrent.

Jenna Millikan: 425-339-3035; jenna.millikan@heraldnet.com; X: @JennaMillikan