BRISTOL — A 56-year-old resident was killed Sunday night after a truck crashed into a tree, police said. Police identified the driver on Tuesday afternoon as Nelson A. Thibeault of Hiltbrand Road. The cause of death was smoke inhalation. The accident occurred shortly before 6:30 p.m. on Stafford Avenue at Jewel Street, and the truck caught on fire, officials said. The flames were so intense that the eyewitnesses were unable to pull the victim out of the truck, police said.