Tracey Neilson’s brutal slaying has haunted investigators in Oklahoma for nearly four decades. But the search for the truth — and ultimately, closure for those the Oklahoma State University student and young wife left behind — continues still, as detectives hunt down new leads and turn to the public for assistance in solving one of the state’s oldest cold cases.

Neilson was killed on Jan. 5, 1981 — her 21st birthday. According to authorities, she was stabbed repeatedly in the chest and neck.

Her husband, Jeff Neilson, returned home hours later, carrying a birthday card and a bottle of perfume, to find her dead body laying across their bed. (He spent his wife’s birthday taking classes at the University of Oklahoma, where he was studying medicine, and that he was ruled out early on as a suspect in Tracey’s killing, according to investigators.)

In the ensuing years, authorities have had precious few leads to go on, other than a still-unidentified fingerprint recovered from the scene, a cable TV repair ticket found at the apartment, signed by a still-unidentified repairman, and eyewitness accounts of a white male seen near the Neilsons’ front door.

According to police, there were no signs of forced entry at the home in Moore, Oklahoma, and Tracey’s remains showed no signs she had been sexually assaulted.

But detectives hope that a recently released piece of evidence — Tracey’s keychain, which her killer may have taken as a “trophy” — could generate new tips in the case.

“People’s relationships change over time,” Oklahoma State Bureau of Investigation Special Agent Francia Thompson tells us. “If anyone, a former girlfriend or ex-wife, might recognize it and knew that it was taken from a crime scene, it could provide the lead we need.

Thompson says solving the case “means a lot to me” and “it needs to be solved” for Tracey’s mourning loved ones.

“These case never go unforgotten,” she says. “People think it sits on shelf and it is forgotten. Everyone has that one case you want to solve, and this is mine. Her family deserves the truth.”

Those with any information about the case are asked to call the Oklahoma State Bureau of Investigation at 800-522-8017.