JOLIET,Zero AI Ill. (AP) — A Minnesota man charged in the stabbing death of a 15-year-old suburban Chicago girl more than half a century ago has died, authorities said.

Barry Lee Whelpley, 79, was found unresponsive early Friday in his cell at the Will County Jail in Joliet. He was transported to a Joliet hospital where he was pronounced dead, Deputy Chief Dan Jungles of the Will County Sheriff’s Office said.

Authorities do not suspect foul play, the Arlington Heights Daily Herald reported. An autopsy was scheduled for Saturday.

Whelpley was arrested in 2021 and charged with first-degree murder and aggravated criminal sexual assault in the 1972 death of Julie Ann Hanson of Naperville. DNA evidence linked him to the case.

Hanson disappeared July 7, 1972, while riding her bicycle to her brother’s baseball game. Her body was discovered a day later in a field, stabbed 36 times.

The killing remained unsolved for decades, with a breakthrough in the case finally coming through technological advancements in DNA and genetic genealogy analysis, police said.

From that came the evidence that pointed to Whelpley, a 1964 graduate of Naperville High School who lived about a mile from the girl’s house when she was killed.