Another cold case in western Washington was solved using DNA technology and genealogy, this time resulting in the arrest of a 55-year-old suspect accused of killing a Federal Way teenager in 1991.

Almost 28 years ago, Sarah Yarborough was found dead near her high school campus. She had been strangled and was left in the woods near Federal Way High School. The King County Sheriff’s Office arrested a suspect and booked him into King County Jail Wednesday night, as announced during a Thursday news conference.

King County prosecutors charged Patrick Nicholas with first-degree murder Thursday. He was held in lieu of $5 million bail.

Yarborough had driven to school at about 8 a.m., before she and the rest of the Federal Way High School drill team went to a match at 9 a.m., according to KCSO’s investigation.

Two brothers were walking through the campus when they saw the suspect, and soon after, Yarborough’s body.

Officers at the scene said her body wasn’t found near her car.

Yarborough’s mother, Laura Yarborough, thanked KCSO’s detectives at the news conference for their determination in solving a case that lasted for almost 28 years.

“They have never given up, even when I had given up. They didn’t give up,” she said.

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Later, Laura Yarborough talked about her daughter, the case and a suspect finally being arrested.

“I’m still a little numb, I’m sure that other feelings will follow,” Laura Yarborough said after she was asked about receiving the call about the suspect being found.

“Sarah was a person who loved life, she loved people, she loved to travel,” she said. “She was an excellent student; she loved school, she loved reading, always had a book in her hand and was excited about going to college.”

Laura Yarborough said the news was hard on her sons and that her 95-year-old father, who had been involved with the investigation from the beginning, had not been told yet.

“I’m sure he’ll be very thankful and very grateful, but his health is a little fragile,” she said.

The DNA found on Yarborough when she was found was tested and developed into a suspect profile, King County Sheriff Mitzi Johanknecht said. Sketches of a man witnesses said was seen near the school’s tennis courts that morning were made as well.

Though a DNA profile of the suspect was made, detectives still didn’t have a name.

In 2011, a KCSO detective reached out to IdentiFinders International, said Det. Kathleen Deckert, KCSO’s lead detective on the case. They were able to “determine some physical attributes of the suspect” and later “general ancestry.”

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It’s been a growing trend in solving cold cases to match suspect’s DNA profiles with names using genealogy to determine ancestry. Some genealogists will build family trees to find a suspect’s name.

The suspect’s DNA was ultimately matched to the DNA found on Yarborough last weekend after KCSO detectives surveilled the 55-year-old Covington man and tested items he had thrown out — similar to Snohomish County Sheriff’s Office detectives grabbing a suspect’s discarded coffee cup to match DNA, solving a 47-year-old murder case.

The unsolved case had been one that county officials said stayed with them for almost three decades. King County Prosecutor Dan Satterberg said prosecutors in his office invested themselves in it over the years; Johanknecht said many detectives had worked on the case over the years.

SeattlePI reporter Alex Halverson can be reached at alex.halverson@seattlepi.com. Follow him on Twitter @AlexHalversonPI. Find more from Alex here.