Joyce Gregory was about halfway through her morning school bus route when she stopped to pick up 14-year-old Jason Clinard. But police believe that instead of getting on the bus early Wednesday, Clinard fatally shot Gregory with a .45-caliber handgun, an act apparently prompted by an argument over Clinard's use of smokeless tobacco.

None of the 24 students on the bus, ranging in ages from 5 to 17, were hurt.

The shooting happened about 6:15 a.m. just outside Cumberland City, about 50 miles northwest of Nashville. Gregory, a 47-year-old married mother of two daughters, was picking up students and taking them to Dover Elementary and Stewart County High School.

Two weeks ago, Gregory told family members she was having trouble with students "dipping snuff" on the bus, according to her cousin, Jacqueline Reed. After several warnings, she reported them to school administrators Tuesday, Reed said. The 14-year-old suspect was among the students.

The boy had not yet boarded the bus when the driver was shot, said Jennifer Johnson, spokeswoman for the Tennessee Bureau of Investigation (search). Police would not say where the boy got the weapon.

Officials gave few details about the shooting and would not comment on a motive for the shooting. They also refused to release the boy's name, but neighbors, schoolmates and Gregory's relatives identified him as Clinard.

District Attorney Dan Alsobrooks said the suspect was charged with first-degree murder in Juvenile Court and was being held without bond. He said the boy could face adult charges as the investigation continues.

Public defender Jack Lockert met with the boy for about 45 minutes.

"I would characterize him as being in shock," Lockert said. "We obviously feel like he has severe mental issues. He's an A and B student and had never been in trouble before."

Clinard was taken to a juvenile detention center in Nashville and will undergo a psychiatric evaluation in the next 30 days.

Gregory was a teacher's assistant for four or five years and had been a bus driver for the past two years, said Phillip Wallace, director of Stewart County Schools.

"I lost a good friend this morning, so I'm hurt," said Bill Austin, a supervisor for Stewart County schools. "We're trying to do our level best to get our kids through this. That's what we've got to do right now."