Eric Singer was a true child of the ’60s. With long hair, bell bottoms and a guitar slung over his shoulder, he quit college and, to escape the potential of fighting in Vietnam, he considered leaving Ohio for Canada.

In 1973, at the age of 22, a backpack-carrying Mr. Singer vanished. He was last seen on his bicycle in Cleveland.

“He had left his beloved guitar, which almost never happened, so he was in a hurry and he hadn’t even stopped to pick up his paycheck” at a hospital where he had been working, said his older sister, Ruth Singer.

His family filed a missing persons report at the time. They eventually hired a private investigator and they searched for Mr. Singer, who commonly went by Ricky.

More than 50 years after last seeing him, Ms. Singer was in her living room in New Mexico when she got a phone call from an unidentified number.

It turned out to be Sgt. Philip Holmes, a detective from the Ontario Provincial Police in Ontario, Canada, which announced the result of an investigation on Thursday.