Niagara police say they are trying to track down a man on a bicycle who allegedly sexually assaulted another man in Niagara Falls this morning.

It happened between 2:30 am and 5:30 am, police say, in a parking lot in the area of Robinson Street and Fallsview Boulevard.

That's when an "unknown male" sexually assaulted a male victim, police say. "This male was riding a bicycle," a police news release reads.

The man is described as white and between 30 and 40 years old, with a thin build, blonde hair possibly in a ponytail and a goatee.