Police from Toronto and Durham Region are searching Lake Ontario after an empty boat was found on the water.
Durham police say the owner of the boat found off the Toronto waterfront is from Oshawa and is unaccounted for.
The almost five-metre boat turned up near Ashbridges Bay on Saturday afternoon.
Five vessels and two helicopters from CFB Trenton are scanning the water between Ashbridges Bay and the Toronto Islands.
A CFB Trenton spokesman says searchers used the boat's ID markings to track down the names of the owner of a parked vehicle and the boat's owner.
Capt. Jean Hood says that despite speaking with family members, officials don't know how many people might have been on the boat, which only had one lifejacket.