Collingwood and the Blue Mountains Ontario Provincial Police (OPP) are investigating a sexual assault. Police say the assault occurred on a trail in Collingwood, in the area of Huron Street and Niagara Street, Wednesday at around 11:30 p.m. Police describe the man as: The young man was riding a dark-coloured mountain bike with wide, aggressive tire treads. The rider appeared to lean forward while riding the bicycle. Police are asking anyone who has information or who may have been in the area at the time, to contact the OPP non-emergency line at 1-888-310-1122.