CANTON, Miss. (AP) — A man got out of his pickup, walked up to the defendant in a drug-dealing case and fatally shot him in the chest, then set down his gun and surrendered as deputies confronted him outside a Mississippi courthouse Monday morning, law enforcement officials said.

Police and other officials said they weren't sure why the suspect — 24-year-old William B. Wells, a former Canton firefighter with no history of trouble — would shoot victim Kendrick Armond Brown.

Brown was in a small courtyard outside the Madison County Courthouse with his lawyer when he was shot, District Attorney Michael Guest said. Brown, 37, faced charges of selling cocaine and was a habitual offender who had been sentenced to prison time on past drug counts, according to an indictment. He was expected to reject a plea offer on his latest charges Monday, Guest said.

Wells was in the county jail with a bail hearing set for 10 a.m. Tuesday. Before Monday, "he hadn't been in any trouble or anything," Canton police Chief Otha Brown said.

But on Saturday night, the chief said, Wells' mother was shot and wounded while in her car. She drove herself to the Canton Police Department, reported that she'd been shot, and was transferred to a hospital in an ambulance, according to police. The chief refused to give her name, citing the ongoing investigation.

Earlier, Guest described the relative in the Saturday shooting as a female "informant." He said officials didn't know whether the shootings were linked.

On Monday, the shooting unfolded quickly, Sheriff Randy Tucker said. There are metal detectors inside the courthouse door, but the parking lot is open to the public and unguarded. The Canton Police Department sits at the rear of the parking lot, less than 200 yards from the front door of the courthouse.

After the shooting, officers searched with metal detectors under crepe myrtle trees, looking for the shell from the semiautomatic handgun.

Guest said he thought there was little that deputies could have done to prevent the shooting. "There would have been, in my opinion, no way this could have been stopped," Guest said.

Canton is the seat of Madison County, just north of Jackson. It's a historic antebellum town with about 13,000 people and is known for its Christmas light festival on the town square. Canton also is the home of a Nissan assembly plant that employs 6,000 people. The south end of the county is a rapidly growing suburb; the northern half is poorer.

The 1996 movie "A Time to Kill," based on John Grisham's novel, was filmed in part at the courthouse. In the movie, a father played by Samuel L. Jackson goes to court and kills two men on trial over the rape of his daughter.