EVERETT — Thirty years ago, the double-murder of young Vancouver Island couple Jay Cook and Tanya Van Cuylenborg left a trail of clues that circled Puget Sound.

The killer’s identity has baffled police in two countries for three decades. Now, for the first time, detectives might have caught a glimpse of his face, and they’re sharing it with the public.

Advances in DNA forensic technology helped experts to build three composite images of the suspect’s likely appearance, an estimate of what he would look like at ages 25, 45 and 65. He has fair skin, hazel eyes, freckles and reddish-blond hair, in pictures unmasked Wednesday by the Snohomish County Sheriff’s Office.

The faces are educated guesses, based on genetic makeup of DNA found on crime scene evidence. They are not photos. The technology can’t reveal the suspect’s age, weight, haircut, facial hair, scars or tattoos. But detectives hope the images bear enough of a resemblance to trigger someone’s memory.

The families of Cook and Van Cuylenborg announced the reward for a tip leading to the killer — whether he is dead or alive — will be raised to $50,000. The offer expires Dec. 31.

Tips can be directed to the sheriff’s office at 425-388-3845. Detectives ask people to give their names, so police can ask followup questions.

A trip around the Sound

Cook, 20, and his girlfriend, Van Cuylenborg, 18, were last seen alive Nov. 18, 1987. They were outgoing and perhaps a little naive, Snohomish County cold-case detective Jim Scharf said.

“The family said Jay was the type of person who would give a hitchhiker a ride if they needed one,” Scharf said.

Laura Baanstra recalled Cook hadn’t eaten anything that day at their home in Saanich, British Columbia. She was having a sandwich, and she reluctantly gave her brother a piece of it when he asked. He waved goodbye to her as he drove off in a bronze 1977 Ford Club Wagon, to pick up his girlfriend.

“When your brother, or sister, or daughter, or a loved one walks out the door, you have no way to know that it’s the last time you’re going to see them,” Cook’s sister said.

He planned to retrieve parts for a furnace for his father from Gensco, a business in the industrial SoDo District of Seattle. The couple boarded the Coho ferry in Victoria.

They arrived in Port Angeles at 4 p.m., with an hour of daylight left. They headed southeast on Highway 101, skipped a turnoff for the Hood Canal Bridge and continued for miles on 101 into Hoodsport, where they bought snacks at a deli.

The couple made another pit stop at Ben’s Deli in Allyn, near the south end of the Kitsap Peninsula. Clerks later reported to police they asked for directions to Bremerton. The clerks did not see a third person with them, according to the sheriff’s office. The couple bought a ticket for the ferry from Bremerton to Seattle at 10:16 p.m. Days later the receipt was found in the van.

“It’s always been presumed that they did make it onto the ferry,” Scharf said. “That was the last documented evidence of where they had been.”

It’s an hour-long ride. They might have met someone on the boat or in Seattle, but police have struggled to pinpoint where. Perhaps they needed to stop for directions again, and then were abducted, Scharf said. Detectives know the couple never showed up at Gensco to pick up the money-ordered parts.

The murders

Van Cuylenborg’s partly clothed body was found six days later, Nov. 24, 1987, about 20 yards off Parson Creek Road in Skagit County. She had been restrained with zip ties, raped and shot in the back of the head with a .380-caliber pistol.

Jennifer Sheahan-Lee, then an 18-year-old volunteer with search and rescue, was tasked with looking for evidence near the body. She recalled it was a typical windy and rainy Pacific Northwest day, as the team sifted through wet dead leaves and foliage in search of clues about a half-mile west of Prairie Road. She found the shell casing for a bullet.

“It was right before Thanksgiving, just days before,” Sheahan-Lee said. “This family was never going to celebrate a holiday with their family member again. We just felt the drive to give them some answers.”

In a sense, she’s still searching. Sheahan-Lee is now a Skagit County sheriff’s sergeant who oversees the local detective in charge of the case.

“It’s amazing to think that 30 years later that we’re still working this case, with little evidence … to go on,” she said.

Van Cuylenborg’s wallet, her ID, the keys to the van, a pair of surgical gloves and a box of .380-caliber ammo were found Nov. 25, 1987, under the back porch of a tavern, Essie’s, that has since closed in downtown Bellingham. It was next door to Rumors Cabaret. The Ford was parked a block east, by the old location of a Greyhound bus station.

A witness recalled the van hadn’t moved for at least four days in the Blue Diamond lot. Van Cuylenborg’s clothes were in the vehicle. Police recovered critical DNA evidence from the van.

The next day, Thanksgiving 1987, the body of Jay Cook was discovered in Snohomish County. Passersby found him dead under the High Bridge on the Snoqualmie River, southwest of Monroe.

Cook had probably been killed first, Scharf said, as the van motored north through Snohomish, Skagit and Whatcom counties. The driver might have taken Highway 9, a less visible route than I-5. One tip suggested the van was seen in Bryant, near Arlington, while Cook and Van Cuylenborg were still missing.

Cook’s body had been covered with a blue blanket that didn’t belong to the couple. He had been beaten with a rock and strangled with braided twine, Scharf said. The twine appeared to have been part of the bedding they brought with them for the trip. Zip ties were found near Cook, at the site off Crescent Lake Road.

The scene was less than a mile from a state prison honor farm, a dairy farm for low-risk inmates. Sometimes prisoners would sneak out to meet girlfriends or buy drugs at a spot by the bridge, said Scharf, who used to patrol the area. It led police to wonder if the killer might have spent time in prison. But DNA databases for prisoners only go back so far.

A 30-year investigation

Over the years, the DNA of the suspect has sat waiting for a match in the federal CODIS database and its equivalent in Canada. There has never been a hit from a new felon or an unsolved case.

Scharf suspects the murderer carried a backpack with tools for killing — zip ties, a gun, gloves — as he hunted for victims. Serial killers who were known to be active in the Pacific Northwest at the time have been ruled out by DNA.

Tips poured in when the case aired on the television show “Unsolved Mysteries” in the late ’80s. About 350 names made up a list of possible suspects. Most have been ruled out. A few remain.

“It’s something that you just never give up on,” Scharf said. He has been assigned to the case for 12 years.

Some breakthroughs took decades to develop. A week after the deaths, the families of the victims started receiving horrifying letters from someone who claimed to be the killer. Scharf traced them in 2010 to a homeless man living in Western Washington. He explained that he’d fixated on the case at a time in his life when he was angry at Canadians. His DNA didn’t match the killer’s. He was crossed off the list.

With so many leads exhausted, this year the sheriff’s office turned to Parabon NanoLabs, a Virginia-based company that uses DNA to build digital faces of people in unsolved killings or unidentified remains. It’s the first time the county has made use of the technology.

About 150 cases in three years have been processed by the DNA phenotyping software known as Snapshot, Dr. Ellen Greytak said. Parabon’s analysis can rule out certain traits, narrowing the pool of suspects. In this case, the experts are more than 90 percent sure the suspect’s ancestry is northern European and that he has fair skin. The man had the gene for male pattern baldness.

The tool has helped to solve cases up to 25 years old, Greytak said. They hope a resolution for these killings will set a new record.

Meanwhile, Scharf and other investigators also are looking for more traditional ways of following the killer’s tracks.

When the van was found, it was missing Cook’s green canvas backpack, his black ski jacket and a 35 mm Minolta X-700 camera that belonged to Van Cuylenborg. The camera had the serial number 2067048. Its lens was recovered in 1990 at a pawn shop in Portland, Oregon. Apparently the lens had changed hands several times, but the body of the camera wasn’t found.

Detectives would like to speak with anyone who noticed a person who suddenly acquired that kind of camera and the other items in the late ’80s.

Scharf also would like to speak with anyone who worked at E.A. Nord Door in 1974, on the Everett waterfront. He says there is a possible connection, something he had not shared until now.

Both families still hold onto hope.

Cook’s sister stood alongside three giant posters of the digital faces at the news conference Wednesday. Without glancing to her left, she said she hadn’t been able to look at the man’s face yet.

At one point Cook’s brother-in-law, Gary Baanstra, stepped in to help his wife answer questions from about 20 journalists from the United States and Canada. He said they have tried to focus on their best memories of Jay.

Caleb Hutton: 425-339-3454; chutton@heraldnet.com. Twitter: @snocaleb.