ARKABUTLA, Mississippi (AP) — A lone gunman killed six people including his ex-wife and stepfather Friday at multiple locations in a tiny rural community in northern Mississippi, the sheriff said, leaving investigators searching for clues to what motivated the rampage.

Armed with a shotgun and two handguns, 52-year-old Richard Dale Crum, who a family friend said had a history of mental illness, opened fire at about 11 am and killed a man in the driver’s seat of a pickup truck parked outside a convenience store in Arkabutla, near the Tennessee state line, Tate County Sheriff Brad Lance said.

Deputies were working the crime scene when a second 911 call alerted authorities to another shooting a few miles away. After arriving at a home, they found a woman, whom the sheriff identified as Crum’s ex-wife, shot dead and her current husband wounded.

Lance said deputies caught up with Crum outside his own home and arrested him. Behind the residence they found two handymen slain by gunfire — one in the road, another in an SUV. Inside a neighbouring home, they discovered the bodies of Crum’s stepfather and his stepfather’s sister.

“Everybody has crime, and from time to time we have violent crime, but certainly nothing of this magnitude,” Lance said in an interview. He added: “Without being able to say what triggered this, that’s the scary part.”

Crum, 52, was jailed without bond on a single charge of capital murder, and Lance said investigators were working to bring additional charges. It was not immediately known if Crum had an attorney who could speak on his behalf.

That initial murder charge was for the killing of Chris Eugene Boyce, 59, the man who was shot outside the store. Boyce’s brother was in the truck with him at the time and fled, according to the sheriff. Lance added that Crum chased the brother through a wooded area before he escaped unharmed.

Deputy Tate County Coroner Ernie Lentz identified the others killed as Debra Crum, 60; Charles Manuel, 76; John Rorie, 59; George McCain, 73; and Lynda McCain, 78. Lentz also said Boyce was from Lakeland, Florida.

Ethan Cash, who lives near the store, told WREG-TV he heard a gunshot from inside his house.

“I had just woken up and I look back here, and I see dude walking back here with a shotgun,” he said.

Cash added that he went to the scene and found one person who had been shot. He checked for a pulse, but found none.

In the lobby of the Sheriff’s Office, Norma Washington told The Associated Press that Boyce was her nephew. She said he and the brother, Doug, who lives in Alaska, had been in town cleaning up a property they inherited from their deceased uncle.

“I lost my brother, and now this one,” Washington said. “This has been something else.”

It was unclear whether Crum knew either of the brothers.