DNA on Discarded Cigarette Helps Lead to Arrest in a 1981 Homicide

The 1981 fatal beating of a steelworker in northwest Indiana remained unsolved for so long that the son of the original detective on the case started reinvestigating it in 2018 — and helped solve it.

Blood from the crime scene and a discarded cigarette tossed out a vehicle window at a 2023 traffic stop in Illinois eventually led to the arrest of Gregory Thurson, 64, of Eugene, Ore., on Oct. 29 on a murder charge in the death of John Blaylock, Sr., 51, who was killed in his apartment in Griffith, Ind.

That capped an investigation that began on Nov. 3, 1981. On Wednesday, Mr. Thurson, who was arrested in Oregon and extradited, is to appear in a Lake County, Ind., courtroom. His lawyer with the Lake County Public Defender’s Office could not be reached for comment on Tuesday.

It is unclear what the motive for the killing was and what relationship there may have been between Mr. Blaylock and Mr. Thurson.

“I can’t say enough about his hard work and how gratifying it is to me that he was able to come behind me some 43 years later and put this all together,” Retired Detective John Mowery Sr. of the Griffith Police Department said of his son, Detective John Mowery Jr. “When he sinks his teeth into something, he just he stays with it.”

On Nov. 3, 1981, two worried steelworkers went to Mr. Blaylock’s building on a Tuesday afternoon, after he didn’t show up for his shifts on Monday or Tuesday morning. The Sunday newspaper was still outside his apartment door, which was locked, and they waited while two building employees used a master key to get inside.

The employees found Mr. Blaylock, a father of three, lying face down on the floor of his bedroom in a pool of blood, according to an affidavit prepared by Detective Mowery Jr. Mr. Blaylock was wearing a white T-shirt and was naked from the waist down.

A detective soon arrived and found hair and body tissue embedded in the shards of a pottery piece, the police said. A broken digital clock, which read 2:19, was found at Mr. Blaylock’s feet. He was wearing a watch that had stopped at 2:15 and 43 seconds. The date read Sunday, Nov. 1, 1981. The authorities ruled the killing a homicide and said he died from a skull fracture due to blunt force trauma.

Detective Mowery Sr. was among the detectives assigned to work on the case. They quickly learned that Mr. Blaylock was a regular at a nearby bar, and that he had last been seen there in the early hours of Sunday, Nov. 1. One of the workers at the bar told the police that she had seen Mr. Blaylock with a younger man whom she had not seen before.

“We conducted a lot of interviews,” Detective Mowery Sr. recalled in an interview on Tuesday. “We did a lot of running down leads. We put a lot of time and effort into that case, but we just couldn’t put an identity to the evidence.”

He retired in 1994 after 25 years with the department, and he often thought about the unsolved case. His son joined the department in 1998.

In recent years, the Griffith Police Department decided to revisit open homicide cases. Detective Mowery Jr. opened the old case file on the Blaylock killing in 2018 and re-interviewed the detectives who had worked on the case in the early 1980s — including his father. He learned that the investigators back then believed that the suspect had been cut and had bled during the attack.

“Back in 1981, there were limits with what blood evidence would show, DNA wasn’t a part of police work in 1981 and neither was CODIS,” Detective Mowery Jr. said, referring to the Combined DNA Index System, an F.B.I. database of DNA profiles from biological evidence found at crime scenes. “We talked about that and the few people that they interviewed back then that would’ve been the last people to see John Blaylock alive, as well as where John Blaylock liked to spend his time in the days leading up to the crime.”

Looking at the photographs of the evidence, Detective Mowery Jr. concluded that the blood found in the bathroom could not have belonged to Mr. Blaylock because the victim most likely would not have been able to make it that far from where he had been attacked.

Detective Mowery Jr. sent a sample of the blood to the Indiana State Police, and a DNA profile was developed in 2018. But no matches turned up in CODIS.

In 2022, he sent the DNA profile to Parabon NanoLabs, a Virginia company whose services include novel DNA-based forensics. This type of genetic genealogy has been used in recent years to solve dozens of other crimes, including the murders tied to the Golden State Killer. Investigators across America are using it to revisit hundreds of unsolved crimes.

It was Paragon’s advanced analysis in the fall of 2022 that gave the Griffith case its first major lead in 41 years, winnowing the suspects to three men, all from the Thurson family. All three had lived in the Griffith area at the time of the crime, according to the affidavit.

One of the men died shortly afterward, but not before Detective Mowery was able to get a hair sample and eliminate him as a suspect. That left Gregory Thurson and his brother.

When the police in Burnham, Ill., a town of about 4,000 residents between Chicago and the Indiana border, pulled Mr. Thurson’s brother over in May 2023, he tossed a cigarette out the window of his vehicle, which an officer later collected. It was sent to the Indiana State Lab, which eliminated him as a possible suspect.

The lab concluded that it was highly likely — or 520,000 times more likely — that the DNA from the blood in the bathroom was from Gregory Thurson.

After his arrest in Eugene, Ore., he was brought to Indiana this month to face charges.

A phone message left for a son of Mr. Blaylock on Tuesday was not immediately returned.

Kirsten Noyes contributed research.