MURFREESBORO, Tenn. – A 20-year-old student pulled out a revolver and shot another man in the thumb during an argument on the campus of Middle Tennessee State University, authorities said Monday. The campus of 24,660 about 30 miles southeast of Nashville was on alert for about 45 minutes.

Police say Justin Macklin, a MTSU student from Memphis, got into an argument and shot at Austin Morrow of Murfreesboro, wounding the 20-year-old former student.

Police said Macklin has been charged with carrying a weapon on school grounds, aggravated assault and reckless engdangerment. He was released on $18,500 bond from the Rutherford County jail, authorities said. A spokeswoman said there was no record of an attorney in the case, and added a court hearing is scheduled March 2.

MTSU Police Chief Buddy Peaster said the two men had problems in the past but he did not say what prompted the shooting or elaborate on what they had argued about.

Police said the shooting occurred outside the student center, and the suspect then fled to a classroom building 200 yards away with Morrow in pursuit. At the building, police say, the suspect left a .32-caliber revolver, his shirt and two bags of marijuana. He was apprehended without incident when he left the building.

University President Sidney A. McPhee praised what he called the quick response by local and campus police. “We very much appreciate also the work done by our campus police and others to keep our community informed about the situation as events unfolded,” he said in a statement.

Morrow was treated on the campus by paramedics. First reports that the shooting happened in a classroom were incorrect, police said later Monday.

The shooting disrupted activities for a time.

Jamie Smith, 20, a pre-dental major, said she was in history class with 50 others when they received a text alert from the school saying there had been a shooting in their building.

“Everybody just started running toward the windows to see what was happening,” she said.

A campus alert was issued at 12:19 p.m. telling students and staffers to stay inside buildings. A subsequent e-mail from the University at 1 p.m. canceled the alert, saying that the suspect was in custody and that the weapon was confiscated. Another alert at 1:29 p.m. gave students and staff the all-clear to go about their business.