AURORA, Colo. – A gunman barricaded inside his Colorado home fired shots at police from a second-story window before he was killed as SWAT officers stormed the home Saturday. Once inside, they found the bodies of three other adults, authorities said.

The suspect, whose name was withheld by police, held officers at bay for nearly six hours after neighbors reported gunfire at 3 a.m. inside the modest townhome in the Denver suburb of Aurora, said police Sgt. Cassidee Carlson. It wasn't known if officers shot the suspect or if he shot himself.

Investigators said two men and a woman appeared to have been killed before officers arrived.