Sanderson, 32, and his brother, Damien, 31, were charged with murder in the stabbing attacks on the James Smith Cree Nation and the nearby village of Weldon on Sunday that killed 10 people and wounded 18 in one of Canada’s deadliest mass killings. Damien Sanderson was found dead on the James Smith Cree Nation on Monday with injuries that authorities said did not appear to be self-inflicted.