RCMP say the 55-year-old man's truck has also seized for examination after a tip from the public.
Forty-eight-year-old Paul Bally was struck Tuesday, and police said the vehicle involved was a Ford truck.
Bally's wife said that whoever hit her husband could have stopped and called for help instead of leaving her to find him in a ditch hours later.
Bally was taken to hospital, where he was pronounced dead.
The suspect's name cannot be released because he has not been formally charged.