An elderly man whose death became a cause for gay rights advocates died of natural causes, not from being beaten, authorities said.

Police also said Wednesday that they intended to close the investigation into 72-year-old Andrew Anthos' death.

"There's no evidence that an assault occurred," police spokesman James Tate told The Detroit News.

According to family members, Anthos said he was riding a city bus home from the library on Feb. 13 when a young man asked him if he was gay and uttered a slur.

Anthos said the man followed him off the bus and confronted him again. Anthos said he told the man he was gay as he went to help a friend whose wheelchair was stuck in a snowbank, according to his cousin, Athena Fedenis.

Anthos said the attacker struck him in the back of the head with a pipe and ran off. Anthos died Feb 23.

His death drew wide attention, and was cited on the floor of Congress by Sen. Carl Levin, a Michigan Democrat, as evidence of the need to extend hate crime legislation to gays.

But the Wayne County Medical Examiner's Office concluded that Anthos fell because he had an arthritic neck, and detectives were unable to find witnesses to a beating, police said. Medical Examiner Dr. Carl Schmidt said evidence did not support the report of an attack on Anthos and said a head injury likely came from falling.

It was unclear what police made of the friend's account. Messages seeking comment were left by The Associated Press, but were not immediately returned.

Fedenis said she was shocked.

"I won't let this rest," Fedenis said. "I can't let this tarnish him. I don't want anyone to think it wasn't a hate crime."