Police tape surrounds one of the crime scenes in Tyrone, Mo., on Friday.

TYRONE, Mo. — A man who authorities say might have been unhinged by the death of his ailing mother went on a house-to-house shooting rampage in a small town in the Ozarks, killing seven people before taking his own life.

Joseph Jesse Aldridge, 36, carried out the killings with a .45-caliber handgun Thursday night or early Friday at four homes in Tyrone, according to the Missouri State Highway Patrol. Aldridge’s body was found before dawn Friday in a pickup truck in a neighboring county. No suicide note was found.

The patrol said four of the dead — two couples — were cousins of Aldridge’s. The names of three other victims and a person who was wounded were being withheld.

Authorities said the motive remained unclear. But investigators found Aldridge’s 74-year-old mother dead, apparently of natural causes, on a couch at the home she shared with her son, officials said.