02/28/2026
I remember this case vividly! It was a few months before my wedding. Had many people scarred they would be next!
BILL AND MARY – ONE OF OHIO’S COLDEST CASES
On February 27th, 1970, 20-year-old Mary Petry arrived at the off-campus apartment of her boyfriend, 22-year-old Bill Sproat in Columbus, Ohio. They planned to spend the weekend together, but that Friday turned into a night of unimaginable horror.
The next day, their lifeless bodies were discovered. They’d been badly beaten, strangled, and stabbed numerous times and yet no one in Bill’s apartment building heard anything strange that night. The brutality of the crime suggested that the killer knew one or both of the victims and yet, the two quiet, well-liked students seemed to have no enemies.
So, who killed Mary Petry and Bill Sproat?
Mary Jane Petry was born on October 12, 1949, in Portsmouth, Ohio. She was one of five children of Paul and Marcella Petry, and she had a very close bond with her twin sister, Martha. Mary was an excellent student, kind, deeply religious, and had a love of the French language and culture. She earned an award for best international student after spending time abroad in the summer of 1968.
In 1970, she was a third-year student at Mount St. Joseph in Cincinnati, where she studied French. She and Bill, whom she had been dating for over a year at the time of her murder, had been introduced to her by a mutual friend.
William “Bill” Sproat, Jr. was born in Philadelphia in 1947 to William and Mary Sproat and was one of their two children. Bill had already earned a French degree from Xavier University and was doing his graduate studies at Ohio State University when he met Mary. He was also extremely smart, and classmates described him as “quiet but fun-loving, very conscientious about his studies, and a perfectly gentle person.” He and Mary, two introverts with a shared passion for French culture and language, hit it off immediately.
On that February 27th afternoon, Mary got a ride from her university with four other young women. One of them, Terry, said that she and Mary were dropped off at a Holiday Inn in Grove City, where each had plans to be picked up by someone. Terry’s father, who had arrived to pick her up, didn’t like the idea of leaving Mary stranded in the hotel lobby, but Mary assured him that Bill was coming soon, so Terry and her father left.
For some reason, Bill never showed up. It’s been reported that he was working on an important paper that day, so perhaps he lost track of time. Regardless, Mary had to make other plans. She called Bill from the Holiday Inn at 5:15 PM and told him that she was going to take a cab to his apartment. Bill’s roommate and longtime friend left at approximately 6:00 PM to go stay at his girlfriend’s place.
Mary was dropped off by the cab driver at 6:30 PM and what happened after that remains a mystery.
When interviewed later, none of Bill’s neighbors recalled anything that caused them alarm on Friday night. They did notice the door to the apartment was partially open that evening – and they heard music inside – but none of them checked inside.
Around 8:00 PM, a paperboy came to the building to collect money, but he passed by Bill’s door since he wasn’t a customer. When he left, he ran into a man on the front porch who rudely told him to “get the hell out of here.” It was dark outside so the paperboy didn’t get a good look at the man but said he looked “fairly young.” Whoever this man was, he was never identified.
The next day, Bill’s roommate returned to the apartment and found a horrifying, blood-soaked scene – Bill and Mary had been murdered. He was in the bathroom, and she was in one of the bedrooms. He immediately called the police.
The autopsies that followed determined that Mary had been stabbed 23 times, mostly in the back. The uniformity of the wounds suggested she was already incapacitated or dead by the time they occurred. She had sustained multiple blunt force trauma injuries to her head, fracturing her skull. She had also been strangled. There was still a cord around her neck with scratches around it that indicated Mary had struggled desperately to remove it. It was unclear if she had been r***d, but it was strongly suspected that she had been. She was n**e from the waist down and, notably, semen from an unknown man was reportedly recovered from the bed on which her body was discovered.
Bill had suffered the same types of injuries as Mary. He’d been subdued with wire hangers, stabbed 16 times in his back, strangled and struck multiple times in the head. His skull had also been fractured but – unlike Mary – it appeared that Bill was alive when he was stabbed.
The killer had left few clues behind. A small amount of money was missing from the apartment, as well as a rug and an umbrella. Weirdly, the rug was found in the back of a local delivery truck a few days later, but how it got there and who put it there was never determined. There was also a set of bloody fingerprints found on the headboard of the bed where Mary was discovered but they didn’t match any suspects on file. The police also found fragments of a torn letter that mentioned $50 in the garbage can, but there was no context to explain the significance of the money.
There were no signs of forced entry to the apartment, which caused investigators to surmise that the killer was someone who was known to them. Because of that, Bill’s roommate became an early person of interest, although he had a solid alibi since he’d been with his girlfriend. Years later, DNA evidence definitively excluded him as a suspect.
The police also ruled out the cab driver who’d dropped off Mary. His company had time logs that showed he continued to work after leaving Mary at the apartment.
The brutality and violence of the crime shocked and frightened the community. The family and friends of Bill and Mary were devastated. No one who knew them — knowing they had no enemies — could comprehend how anyone would want to hurt them. People who lived in the area worried that they might be next.
In fact, on the same day that Bill and Mary’s bodies were discovered, a woman who lived just a half-block away reportedly fought off an attacker who attempted to force his way inside her apartment. This incident caused the police to consider the possibility that the killer might have been a stranger who simply knocked on Bill’s door and, when Bill or Mary answered, forced his way in. Or perhaps someone had fabricated a story to get into the apartment, perhaps claiming they needed to use the phone.
If that wasn’t the case, then it meant that someone had purposely targeted one or both of them, which seemed baffling since detectives were unable to find anyone who would have wanted to hurt either of them.
Investigators followed every lead they had, but what little they could find led them nowhere. It wasn’t long before the case turned cold. Today, the tragic killings of Mary Petry and Bill Sproat – one of Ohio’s oldest cold cases -- remain unsolved. However, detectives and family members still have hope that one day some new evidence might finally bring the couple’s killer to justice.
