WATERLOO -- Regional police are investigating after a 15-year-old girl was allegedly sexually assaulted in Waterloo.

Police said the girl was walking in the area of Caroline Street and William Street around 8:45 p.m. when she was approached from behind by an unknown man and sexually assaulted.

The suspect is described as a white man, around six feet tall with greying black hair and a beard. He was wearing a white button up shirt, black dress pants and was carrying a messenger bag.

Anyone with information is asked to contact police or Crime Stoppers.