(Photo By Charles Biles/The Associated Press)

Warning: This story contains graphic details and may not be suitable for everyone.

A 56-year-old Seattle man convicted of murdering a Saanich couple over 30 years ago has just officially received two life sentences to be served consecutively with no chance of parole for the crime.

See also: 56-year-old Washington man found guilty in murder of Saanich couple killed in 1987

The man, William Earl Talbott II, was accused of murdering 18-year-old Tanya Van Cuylenborg and 20-year-old Jay Cook of Saanich when they were on a vacation in Washington State in 1987.

Police found Van Cuylenborg’s body down an embankment in a rural area of Skagit county; she was naked from the waist down, and had been shot in the back of the head.

Two days later, hunters in the area found Cook’s body near a bridge over the Snoqualmie River in Monroe. According to police, he had been beaten with rocks and strangled with twine and two red dog collars.

The couple’s vehicle was found some time later near a bus station in Bellingham with Van Cuylenborg’s pants inside. American authorities say that semen found on the pants matched DNA found on her body.

While police launched a massive investigation at the time, Talbott’s conviction occurred over 30 years later thanks to advances in genealogical technology.

See also: New DNA evidence could help solve 1987 murder of young Victoria couple

A genealogist, CeCe Moore, used a public genealogy database to find cousins of the person who left DNA at the scene. She then reverse-built a family tree and determined the source of the DNA must be from a male child of William and Patricia Talbott. William Earl Talbott II is their only son.

Talbott’s DNA, plus evidence like blood and Talbott’s palm print found in the couple’s vehicle, lead the jury to find him guilty.

Meanwhile, Talbott maintains his innocence, with his defense attorney claiming that the DNA discovered does not necessairly prove rape or murder. He says the semen found on Van Cuylenborg’s pants was a result of a consensual act.

Before the sentence was announced, Talbott addressed the judge, saying “I stand before you a man convicted of a crime that I did not commit.”

After the sentence was delivered, Jay Cook’s younger sister, Laura Baanstra, replied “no words sum it up better than ‘Thank God.’ Talbott is finally off the streets.”

Talbott’s attorneys say they plan to appeal the guilty verdict.

With files from KOMO News.