Ryan Wolfson, 41, faces murder charges in the death of Frédérick Murdock, who was found dead in Sainte-Marguerite-du-Lac-Masson, about 100 kilometres northwest of Montreal, on Oct. 10.
Pierre-Paul Fortier was killed on Oct. 18 in Saint-Sauveur, nearly 25 kilometres away from where Murdock's body was found.
Wolfson also faces three charges of attempted murder and possession of unauthorized weapons.
Benjamin Hudon-Barbeau, 36, and Michael Gordon, 29, were also arrested on similar charges.
Hudon-Barbeau is accused of possessing unauthorized weapons and failing to abide by previous court rulings. He was not allowed to communicate with anyone with a criminal file or to possess a firearm.
Gordon also faces gun-related charges.
The provincial police said more accusations could be made as the investigation progresses.