Investigators say they've identified a suspect in a Washington county's oldest cold case using genetic genealogy and DNA from a discarded coffee cup. CBS affiliate KIRO reports 77-year-old Terrence Miller was arrested at his home Wednesday in the 1972 murder of 20-year-old Jody Loomis. Loomis was last seen Aug. 23, 1972 riding her bike from her home in Mill Creek, north of Seattle, to the pasture where her horse was boarded.

She never made it to the field. Later that day, an 18-year-old girl and her friend found Loomis near death in a heavily wooded area. She had been sexually assaulted and shot in the head.

The woman who found Loomis as a teen, Cathy Lenac, told KIRO she drove the mortally wounded woman to a hospital, but a doctor there informed her that Loomis had died.

Terrence Miller, left, was arrested Wednesday in the 1972 death of Jody Loomis, right KIRO

"I pretty much remember it like it was yesterday," Lenac told KIRO. "Sometimes, those types of things you never forget."

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In 2008, the Washington State Patrol crime lab was able to develop a suspect DNA profile from body fluid found on Loomis' boot. But the profile didn't come up with a match in the national criminal database. Then, in July of 2018, Snohomish County investigators sent the unidentified profile to Parabon, a private Virginia-based labs that conducts DNA analysis using genetic genealogy. The emerging DNA technique has gained popularity among law enforcement since it was used in California last year to identify Joseph James DeAngelo as the suspect in the notorious "Golden State Killer" case, though it has raised privacy concerns.

The technique utilizes public DNA databases, where users who have obtained their own DNA profiles from commercial companies such as Ancestry.com and 23andMe can upload them to expand their search for relatives. Since DeAngelo's arrest, other cold case investigators have used unidentified suspect DNA profiles to search the public databases of genetic blueprints in the hopes of finding a "partial match" — a relative — and developing a family tree to narrow down the search for a suspect.

In the Loomis case, Parabon was able to develop a family tree that helped investigators identify Miller as a suspect. In August of 2018, investigators followed Miller to a Tulalip casino, where charging documents say they obtained a coffee cup he discarded and used it to confirm a match to the unidentified suspect DNA profile the following month. Investigators continued to follow Miller to build their case until his arrest Wednesday, the station reports.

"I'm hoping that this will be a closure, for me too," Lenac said of the arrest.

The case had been Snohomish county's oldest unsolved murder, KIRO reports.

"It's exciting for us to have this ability to solve cases and resolve questions that have been around for a long time," said Snohomish County Sheriff's Capt. Rob Palmer.

KIRO reports Miller is charged with first-degree premeditated murder and is being held in the Snohomish County Jail on $1 million bail. Investigators say Miller is not being cooperative and are asking anyone who knew him in the early 1970s to come forward. Investigators want to know what kind of car Miller drove and where he was working at the time, KIRO reports. They are also still looking for Loomis' bridle. Tipsters are asked to contact the Snohomish County Sheriff's Office.