A man convicted of murder in the death of a 16-year-old girl at her Washington high school over 30 years ago will likely spend the rest of his life in prison.

King County Superior Court Judge Josephine Wiggs on Thursday sentenced Patrick Nicholas to nearly 46 years in prison for the killing of Sarah Yarborough, who was found fatally strangled on the Federal Way High School campus in 1991, The Seattle Times reported.

A jury found Nicholas, 59, guilty of first-degree murder and returned a special verdict that Yarborough’s killing was sexually motivated, which allowed for a longer prison sentence.

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Defense attorney David Montes urged the mandatory minimum 20-year sentence, saying Nicholas didn’t commit crimes in the decades since. Wiggs, who had presided over Nicholas’ trial, determined more than 45 years was appropriate because of the facts of the case and his history of sexual violence.

During the trial, prosecutors said Yarborough was an honor student and member of her school’s drill team when she drove to school on Dec. 14, 1991, thinking she was late to meet teammates for a competition. She was an hour early, prosecutors said.

Senior Deputy Prosecutor Mary Barbosa wrote in the state’s sentencing memo that while they will never know how their interaction began, Nicholas in other attacks had approached women with knives, forcing them to walk to secluded areas.

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Patrick Nicholas was sentenced to nearly 46 years in prison for killing a 16-year-old girl at her high school in Washington.

Two boys, ages 12 and 13, who were walking through the school campus that day found Yarborough's body after they saw a man pop up on an embankment and walk away quickly, prosecutors said.

Yarborough's injuries and male DNA found under her fingernails was proof she "fought for her life" before she was strangled, according to the evidence presented at trial.

Detectives after the killing sent DNA samples from dozens of men to the state crime lab to be tested against the unknown male DNA, but none matched. The DNA was afterward periodically but without success run through the Combined DNA Index System, or CODIS, an FBI database of DNA profiles from people convicted of felonies.

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In 2019, a genetic genealogist identified two King County brothers who were sex offenders as possible suspects. The older brother, whose DNA was already in CODIS, was eliminated, leading detectives to focus on Nicholas.

Detectives following him collected cigarette butts discarded by Nicholas near a laundromat in the Seattle suburb of Kent. That DNA matched DNA from the crime scene, and he was arrested, prosecutors said.

Years before, Nicholas at age 19 tried to rape a woman at knifepoint at a park in the eastern Washington city of Richland, but she escaped by jumping into the Columbia River, the state’s sentencing memo says. He was sentenced in that case to 10 years in prison in 1983 but was released after serving over 3 years and was in sex offender treatment and on parole when Yarborough was killed.

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He had previously been sentenced to juvenile custody after raping two King County women at knifepoint, the state's memo said.

Members of Yarborough’s family testified at the hearing about the impact of her murder, KING-TV reported.

"When we lost her, our family was irrevocably changed," said Yarborough’s mother, Lori.