The Envelope That Solved a 40-Year-Old Murder: How Spokane Police Tricked David Tibbett Into Mailing Them His DNA
Illustrative reconstruction, not an authentic photograph of evidence.
On February 4, 2026, Spokane police mailed 74-year-old David Tibbett an official-looking letter about a car he had reported stolen. The letter asked him to confirm the car had been returned and to mail his response back.
The envelope needed to be sealed. Eight days later, it came back to police with a trace of DNA that investigators would compare with evidence collected from Mary Ann Turner’s body nearly 40 years earlier.
In March, the Washington State Patrol Crime Lab reported that the DNA under Turner’s fingernails was 4.3 million times more likely to match the person who had licked the envelope than another person in the United States, according to court records reported by The Spokesman-Review.
That finding helped lead to Tibbett’s arrest on a second-degree murder charge. It did not convict him. As of November 8, 2026, he remained accused, the investigation was ongoing, and the case still had to proceed through court.
Mary Ann Turner’s final hours
Mary Ann Turner was 32 when she was found dead in a Spokane alley on the morning of November 4, 1986. Officers responded at about 7:38 a.m. to a report of a person down near South Ivory Street and East Pacific Avenue. They found Turner in the alley. Investigators determined she had been murdered.
Turner had moved to Spokane from Sacramento. Accounts from newspaper archives describe a woman who had faced hardship and was trying to get by. She had become a mother as a teenager and, at the time of her death, was reportedly looking for a daughter who had run away. These details offer context about her life, but they do not define her. She was more than the circumstances she endured or the case that followed.
Police records and later court documents outlined some of Turner’s last known movements. Her friend Yolanda Snapp told investigators the two had been “working the streets” near East First Avenue and South Magnolia. At around 2:45 a.m., Turner got into a burnt-orange car that drove west along East First.
Two police officers later saw Turner standing alone at Sprague Avenue and North Madelia Street. Her body was found roughly four hours after she entered the car.
Atmospheric illustration only. This is not a photograph of the location where Turner was found.
An early lead that did not become an arrest
Investigators sought information about a bronze car resembling a Ford Torino. According to court records summarized by The Spokesman-Review, an anonymous “secret witness” later told police the vehicle was actually a copper-brown 1975 Ford Elite with body damage. The witness also said Tibbett had been drunk in the area that night and described him as someone who would “weird out with girls.”
That was an allegation from an anonymous tip, not a proven account of what happened. Tibbett owned a bronze 1976 Ford Elite, but the difference in model year and the tip itself did not establish that he had taken Turner or killed her. He was not arrested at the time.
The case remained unresolved. The early vehicle lead did not, on its own, answer the central questions: who had harmed Turner, what happened after she entered the car, and whether the person who left biological evidence could be identified.
DNA evidence, and a long wait
In 2008, retired Spokane detective Kip Hollenbeck submitted swabs collected from Turner’s body (including samples from beneath her fingernails, inside her mouth and from her body) as well as cigarettes left at the scene. Scientists found that DNA beneath Turner’s fingernails matched DNA from semen attributed to an unknown male, according to court records reported by The Spokesman-Review.
The evidence was important, but a profile without a known identity could not identify a suspect by itself.
The next significant step came in 2025, when the Texas forensic laboratory Othram developed a suspect profile using familial genealogy databases. In 2026, Othram suggested investigators examine three brothers: Darrel Robert Tibbett and Daniel Howard Tibbett, both deceased, and David John Tibbett, who was alive. According to the newspaper’s reporting, David Tibbett was still living in the East Decatur home where he had lived in 1986.
Familial genealogy can help investigators narrow a search by identifying possible relatives of an unknown DNA contributor. It is a lead, not a standalone conclusion about an individual’s guilt. Police still needed to test whether DNA from one of the brothers matched the crime-scene evidence.
Illustrative reconstruction, not a photograph of the Washington State Patrol Crime Lab or evidence in this case.
The envelope ruse
Investigators had a practical way to seek a fresh DNA sample without asking Tibbett directly for one. His car had been reported stolen and returned the previous year. On February 4, 2026, police records staff sent him an official-letterhead request asking him to confirm the car was no longer stolen, sign the letter and mail it back in a lick-to-seal envelope.
The letter was not an invitation to discuss the murder. It was a pretext designed to obtain DNA from the envelope. Police received it eight days later. Detective Zac Storment took it unopened to the Washington State Patrol Crime Lab.
In March, the lab reported the comparison result: the DNA found beneath Turner’s fingernails was 4.3 million times more likely to belong to the envelope-licker than to another person in the United States, according to the reporting on the court documents. This is a statistical comparison of competing explanations for the DNA evidence. It should not be read as a 4.3-million-to-one probability that Tibbett committed murder.
The finding was paired with early investigative information, according to Spokane police, who said detectives developed probable cause to charge Tibbett through DNA evidence “in conjunction with witness statements made early in the investigation.” The department credited the Washington State Patrol Crime Lab, Othram and the Spokane County Prosecutor’s Office in its October 21 arrest announcement.
Arrest, and a case still before the court
On October 21, 2026, Spokane Police Department Major Crimes and Special Investigations detectives served a search warrant at Tibbett’s home and arrested him. He was booked into Spokane County Jail on a second-degree murder charge and held on $1 million bond.
At his first court appearance the following day, Tibbett did not speak, according to The Spokesman-Review. Prosecutor Preston McCollam read a statement from Turner’s family, who asked the court to keep Tibbett in custody. The statement included the words: “He has been free longer than Ms. Turner was alive.”
That line reflects the family’s experience of waiting for answers. It does not settle the legal case. Tibbett has been charged, not convicted, and he is presumed innocent unless proven guilty in court.
Newspaper archives also describe Tibbett’s prior legal history, including a 1970 charge of second-degree assault and rape, followed by a guilty plea to assault, and his placement at Western State Hospital in 1971. Those historical records are separate from the evidence in Turner’s case. They should not be treated as proof that he committed this murder.
Confirmed facts, and what remains unknown
Confirmed in public records and reporting: Turner was found dead in a Spokane alley on November 4, 1986. Investigators found DNA beneath her fingernails. A sample from an envelope returned by Tibbett was tested, and the lab reported a strong statistical association between that DNA and the material recovered from Turner. Tibbett was arrested and charged in October 2026.
Still unresolved: What exactly happened after Turner got into the burnt-orange car? Who else, if anyone, was involved? What will the full evidence show in court? Will additional witnesses or records clarify the early vehicle tip? Police have said the investigation remains ongoing and have asked anyone with information to contact them.
Illustrative reconstruction. The map and papers do not reproduce actual police records or evidence.
A breakthrough, not the end of the story
For decades, Turner’s killing was one of Spokane’s cold cases: a real crime story with an early vehicle lead, biological evidence and no arrest. New forensic methods helped investigators generate a direction to pursue. A letter sent for an unrelated purpose then gave them a sample they could compare with the original evidence.
The envelope changed the investigation. But it did not replace the work still required: examining the evidence in court, testing the allegations and hearing what witnesses may know.
The case is also a reminder that an unsolved mystery can remain unresolved for years without becoming forgotten. What further information, if any, might help explain Turner’s final hours?
Sources: Spokane Police Department arrest announcement; The Spokesman-Review, Alexandra Duggan, October 22, 2026; KREM’s account of the investigation.
Tags: Mary Ann Turner, Spokane cold case, forensic DNA, genetic genealogy, unsolved mysteries
Meta description: Spokane police used DNA from a mailed envelope to connect David Tibbett to evidence in Mary Ann Turner’s 1986 murder case. Here is what is known, and what remains unresolved.
Facebook version
Hook: A letter about a stolen car came back to Spokane police eight days after it was mailed. The envelope’s DNA would help reopen a 40-year-old murder investigation.
Mary Ann Turner, 32, was found murdered in Spokane in 1986. DNA evidence existed, but investigators could not identify the unknown contributor for decades. In 2025, familial genealogy gave police a new lead. The following year, they mailed David Tibbett an official-looking request about a car he had reported stolen, with an envelope he would need to lick to seal.
The lab later reported a strong statistical association between DNA beneath Turner’s fingernails and DNA from the returned envelope. Tibbett was arrested and charged with second-degree murder in October 2026. He has not been convicted, and the investigation is ongoing.
The envelope became a turning point, but the case still has to be tested in court.
Caption: An envelope, old DNA evidence and a lead generated through familial genealogy brought new momentum to the investigation into Mary Ann Turner’s 1986 killing. David Tibbett is charged, not convicted. What questions should investigators answer next?
Short Reel concept: Open on a neutral close-up of a plain envelope, labelled Illustrative reconstruction, not actual evidence. Cut to a generic Spokane alley at dawn and a simple date sequence: 1986: Turner found murdered → 2008: DNA evidence submitted → 2025–26: genealogy lead and envelope test → October 2026: arrest. End with the distinction: Tibbett is charged, not convicted. Investigation ongoing.