ARKABUTLA, Miss. >> 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 shocking rampage.

Armed with a shotgun and two handguns, 52-year-old Richard Dale Crum opened fire at about 11 a.m. 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 Lane 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.

Lane 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 neighboring 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,” Lane 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 Lane 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. He had a Florida driver’s license in his wallet, the sheriff said. Boyce’s brother was in the truck with him and fled when Crum attacked, Lane said, and he escaped unharmed.

“I heard the gunshot from inside my house,” Ethan Cash, who lives near the store, told WREG-TV. “I had just woken up and I look back here, and I see dude walking back here with a shotgun.”

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