OPP say side scan sonar is now being used in what has become a recovery mission to find a missing swimmer.
Police have been in an ongoing search since 4:30 p.m. Sunday for a swimmer who disappeared in Lake Erie near Colchester Harbour in Essex County at that time.
A group of boaters went out a kilometer off shore in a 23-foot Boston Whaler and two people reportedly went for a swim near the boat when one of them struggled and went under water. The person missing is a 56-year-old Michigan woman.
The Canadian and U.S. Coast Guard, OPP helicopter, underwater search and recovery unit, K-9 unit, along with Kingsville Fire, Essex Fire, EMS and several volunteers searched the area.
