It happened Saturday at a mobile home on Foss Hill Lane. Authorities say 44 year-old Christopher Dennison of Livermore Falls was killed after he was shot by the homeowner.
Police say Dennis was wearing brass knuckles and a ski mask at the time.
The homeowner, 48 year-old Richard Duffy and his teenage son both escaped injury.
Dennison's autopsy showed he died from multiple gunshot wounds.