Washington State Patrol is launching a new effort to solve a case that went cold more than two decades ago. This one involves a women who died in a traffic collision back in 1991, but was never identified.

WSP cold case investigators went to great lengths and even a graveyard, in search of new leads.

The mystery began on May 14, 1991. That's when a semi truck driver and a female passenger lost their lives in a fiery crash on I-5 near Kalama, in Cowlitz County.

"The girl had been a hitchhiker they believe, and was picked up by this truck driver and there was a fire, so any possible identification she may have had in the truck was destroyed," said Natalie Murry.

Murry is a forensic artist who now knows the details of the case by heart.

The male truck driver was identified. His female passenger was not. In 2014, investigators in search of new leads made the somewhat unusual decision to exhume the body of that unidentified female. Then, investigators asked Murry if she could use the woman's skull to create a sketch of what she looked like.

"You can learn a lot from looking at the bones," said Murry. "There are little indications on the bone that's going to tell me what looks different on your face, what's different about your eyes, where your eyelids attach, how wide your nose is, what direction the tip of your nose is going."

Murry used that information along with witness statements from the 1991 investigation to create the police sketch.

Witnesses reported seeing the woman at a truck stop just before the crash. They said she had long, dark, straight hair pulled back in a ponytail. They also said she was wearing one feather earring, which Murry depicted in the sketch.

WSP circulated the sketch when it was first created in 2014. Investigators are circulating the image again now, in hopes of possibly getting more eyes on it.

"It's getting it in front of the right set of eyes," said Murry. "I had one girl I did a sketch of that had been missing for 40 years, and she was identified after the sketch was put out, so it happens. It's not too late."

WSP said the hope is that the woman's family might see the sketch, and that detectives might be able to finally solve this 26-year-old mystery.

"What we're looking for and what we're trying to do is ultimately identify the female that was involved in this crash," said Chase Van Cleave with Washington State Patrol. "I think any of us putting ourselves in the shoes of having someone in our family go missing, we would want answers. We would want to know what happened to that person. Detectives want to try to bring them closure on this incident."

WSP detectives were also able to extract DNA when they exhumed the woman's body. They say they cross-checked that DNA with the missing persons' database, but so far have not found a match.

If you have information related to the cold case and the events of May 14, 1991 you are asked to contact Washington State Patrol. You can also email the detective on this case at Stacy.Moate@wsp.wa.gov.