The two teenagers suspected of shooting dead Australian tourist Lucas Fowler and his US girlfriend Chynna Deese on a Canadian highway rampage left a "last will and testament" video message.

Kam McLeod, 19, and Bryer Schmegelsky, 19, recorded the video message on their mobile phones before taking their own lives in remote bushland in northern Manitoba, the Toronto Star reported on Monday.

Watch the video above

About 30 seconds of the video was shared with family members of the former fugitives.

McLeod and Schmegelsky said goodbye to their families in the video and described their wishes for their remains, according to a family member interviewed by the Star.

Lucas Fowler and Chynna Deese Credit: Supplied

The video could be the key to explaining why the two teenagers, who weeks before were working at Walmart, would suddenly become killers.

The Royal Canadian Mounted Police are reportedly in possession of the full video recording.

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McLeod and Schmegelsky, from Vancouver Island, were found dead in bushland near Gillam, Manitoba, on August 7, The Royal Canadian Mounted Police announced on August 12 that autopsies pointed to the teenagers taking their own lives.

Two guns were found with the bodies and are undergoing forensic analysis to determine if they are the weapons used to shoot Mr Fowler, 23, from Sydney, and Ms Deese, 24, from North Carolina dead on the side of a British Columbia highway on July 15.

Kam McLeod and Bryer Schmegelsky were suspected of killing Lucas Fowler and girlfriend Chynna Deese. Credit: AP

The couple's Chevrolet van had broken down, leaving them stranded in an area with minimal mobile reception.

McLeod and Schmegelsky are also suspected of killing 64-year-old university botany lecturer Leonard Dyck four days later on another BC highway.

The teenagers drove Mr Dyck's Toyota RAV4 3,000km east to Gillam, sparking a massive manhunt that eventually led to their bodies.

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