A Logan man died after a teenage boy attacked him when the boy's younger sister claimed the man sexually assaulted her on a public bus.

But video footage from the bus showed no assault against the girl, police said.

The 16-year-old girl said she was assaulted about 3 p.m. April 23 on a Cache Valley Transit District bus and immediately told her 17-year-old brother, police wrote in a news statement Tuesday night.

The brother found the man she accused, Michael Fife, 62, who was exiting the bus near 300 South and 100 West in Logan, police wrote. The brother attacked Fife, who suffered head injuries and fell to the ground. Fife was unconscious and lying on the sidewalk when the 17-year-old boy ran away.

About 6:15 p.m. that night, the girl made a sexual assault report to police.

"Logan Police detectives reviewed the video footage of the alleged assault," police wrote. "The video showed Mr. Fife walking past the girl, but no sexual assault occurred."

Four days later, Fife died from his injuries, police wrote.

Police did not release the names of the teenage brother and sister because they are juveniles.