Thirty-two years after the killing of Federal Way High School student Sarah Yarborough, police and prosecutors say they have the man who did it.

“The state is confident that at the conclusion of this case … you will hold that man, Patrick Leon Nicholas, accountable for what he did on that hillside, in the dirt, in the brush, at her school that morning, all those years ago, and that you will find him guilty,” King County prosecuting attorney Celia Lee told jurors April 17 during opening statements in the trial against Patrick Leon Nicholas at the Maleng Regional Justice Center in Kent.

Overwhelming DNA evidence, and circumstantial facts about Nicholas’ life at the time, link him directly to the killing, attorneys argued.

“For what that man did to Sarah,” he is charged with premeditated first-degree murder, Lee told the jury, turning to point at Nicholas, who wore a blue sweater, glasses and a balding head of hair in court. Nicholas, who was age 27 at the time of the killing, is now 59.

There’s no disagreement that Yarborough, 16, was murdered in December 1991, and that her killer went undetected by police and the public for nearly 30 years.

But Nicholas’ defense attorney David Montes told jurors Monday that Nicholas is not that killer.

“He doesn’t match the description because he’s not the person they saw. He’s not the person who killed Sarah,” Montes said. “So how did we end up here?”

The answer, Montes argued, is that after thousands of tips and tens of thousands of work hours, police and the state “needed an answer more than they needed the right answer.”

In desperation, Montes argued, they turned to unproven, even “wacky” technology like hypnosis and polygraph tests, before finally relying on a hobbyist whose “unproven” DNA research methods pointed detectives to the wrong man.

The trial against Nicholas will last at least two weeks. Prosecutors have begun calling witnesses. The defense will have an opportunity to present their case after, and Nicholas will have the option to testify.

So far, testimony has included friends and family of Sarah Yarborough, including her mother; witnesses who saw the killer flee that morning; and the detectives and police who investigated or responded to Yarborough’s murder.

The trial process technically started nearly a month ago, but with pre-trial motions and jury selection complete, attorneys at the King County Superior Courthouse in Kent only just began making their cases to the jury April 17.

The case will largely be decided on DNA evidence, and the scientific advances over the last 30 years that allowed researchers to hone their search down to Nicholas.

Dec. 14, 1991

Sarah Yarborough was a 16-year-old junior, honor student and drill team member who had mistakenly arrived at the school an hour early the morning of Dec. 14, 1991, thinking she was late for an event, Lee told the jury. But from the parking lot, she encountered her assailant, who led or forced her north into the brush by the tennis courts.

It was there that she “fought for her life, where she was sexually assaulted, strangled and killed,” Lee said.

Two boys walked by and saw a man quickly walk out of the brush. They also found Yarborough lying in the brush, and ran home to tell their parents. They described to police a white man with light brown or blonde shoulder-length hair in a mullet style, with redness on his face, possibly due to acne.

Investigators also learned from a jogger who passed by the area that morning and reported seeing the suspected killer kneeling over the girl; sketches were created from these witness accounts.

Coroners determined Yarborough’s assailant strangled her with her own nylons, used as a ligature, as well as manual strangulation. Some of her clothes were in a pile next to her and police found semen stains on some of her clothing.

Throughout the case, DNA evidence found at the scene was reevaluated several times due to the advancement of technology. Detectives reached out in 2011 to Dr. Colleen Fitzpatrick of Identifiers International for assistance in researching the genetic genealogy of the evidence.

Rather than match the entire strain of DNA, researchers established a set of alleles, or versions of specific genes, which tend to vary greatly between individuals.

Eventually, Fitzpatrick landed on two brothers: Edward Peter Nicholas and Patrick Leon Nicholas. The older brother’s DNA was already in CODIS and ruled him out as a suspect.

DNA samples from Patrick Nicholas matched 13 of 13 alleles tested, attorneys said. An undercover officer spoke with him and covertly collected cigarettes and a napkin he discarded for further testing. They matched the crime scene evidence, too.

A male DNA sample from the crime scene matched the sample from Nicholas, and the odds that it would match a random individual from the U.S. population is 1 in 120 quadrillion, Lee said. The state crime lab later determined, for another DNA sample, that it was “590 billion times more likely” that it matched Yarborough and Nicholas than if it matched Yarborough and a random unrelated person from the U.S. population.

Between those odds and Nicholas’ longstanding connections to the area, Lee argued, it’s clear that he was Yarborough’s killer.

Montes disagreed. Fitzpatrick confidently gave the names of other suspects whose DNA closely matched the evidence, Montes argued — until those matches turned out to be inaccurate, spurring her to move on to the next suspect.

“Right here is where you start to see the incredible power of this technology,” Montes said, “(and the) danger when people don’t know what they’re doing (with it).”

And the other evidence doesn’t line up either, Montes said, like the description from witnesses that the killer had a face marked by acne scars.

“Mr. Nicholas does, and has always had, perfectly clear skin,” Montes said. “No acne scars on his face. … How can you say the defining feature does not matter?”