The Royal Canadian Mounted Police said they were sending dive recovery teams to search the Nelson River near Gillam, the small Manitoba town where Bryer Schmegelsky, 18, and Kam McLeod, 19, dumped their stolen Toyota RAV4 on July 23 and disappeared.
Despite unconfirmed sightings of the duo as far away as the neighbouring province of Ontario, the RCMP continue to search around Gillam.
Survival experts predict the teenagers would struggle to stay alive if they attempted to hide in the swampy, bug-infested wilderness around Gillam without shelter and equipment.
The dive team is the latest attempt by the RCMP to bring closure to a manhunt that began more than 3000km away on July 14 in Canada's western province of British Columbia.
The bodies of Mr Fowler, 23, from Sydney, and his North Carolina girlfriend Chynna Deese, 24, were found in a ditch on the side of a BC highway. They had been shot.
Four days later on another BC highway the teenagers allegedly murdered botanist Leonard Dyck and then drove east across Canada's north to Gillam.
Royal Canadian Air Force planes with infrared and other search technology failed to find the fugitives around Gillam.
"To assist in the ongoing search for the 2 BC suspects, Manitoba RCMP's Underwater Recovery Team (URT) will be arriving in Gillam tonight & divers will begin to search a section of the Nelson River tomorrow, Sunday, August 4," RCMP wrote in a tweet.
Canada has been gripped by the nationwide manhunt.
The Ontario Provincial Police announced on Friday it had set up an investigative team to follow up on potential sightings of Schmegelsky and McLeod in their province.
The OPP received more than 30 tips in less than eight hours on Thursday.
