A 21-year-old student killed in a shooting at the University of North Carolina at Charlotte saved some of his classmates' lives by tackling the gunman and attempting to disarm him, the city's top law enforcement official said on Wednesday.

Environmental studies student Riley Howell of Waynesville, North Carolina, one of two campus students shot to death on Tuesday evening, played a key role in ending the attack by a former student, said Kerr Putney, chief of the Charlotte-Mecklenburg Police Department.

"But for his work, the assailant may not have been disarmed," Putney told a news conference.

"He's an athletically built young man, and he took the fight to the assailant. Unfortunately he had to give his life to do so," said Putney, himself a UNC Charlotte alumnus. "He took the assailant off his feet."

The other student killed in the shooting was Ellis Parlier, 19, officials said. Four students left wounded in the attack were identified as Drew Pescaro, 19; Sean DeHart, 20; Emily Houpt, 23; and Rami Alramadhan, 20.

Police in Charlotte arrested former UNC Charlotte student Trystan Andrew Terrell, 22, who has been charged with two counts of murder and four counts of attempted murder. Authorities offered no explanation for a possible motive.

Local news footage on Tuesday showed police escorting the suspect, a tall, lanky figure with shaggy hair from a patrol car. As he was taken into a station house he looked over his shoulder with a smile and yelled a comment to reporters. Television station WBTV quoted the remark as: "I just went into his classroom and shot the guy."

Police said the suspect had used a legally purchased handgun and was carrying a large amount of ammunition. He was familiar with the classroom building where the attack occurred, but it was unclear if he knew the students who were shot, Putney said.

"We can't really discern the why just yet," Putney said. "The randomness is what is most concerning."

He added that police believe Terrell acted alone.

Terrell was due to make an initial court appearance on Thursday afternoon, a spokeswoman for the Mecklenburg County district attorney said. First-degree murder in North Carolinacarries a mandatory minimum sentence of life in prison without parole, and a conviction would make him eligible for the death penalty, the spokeswoman, Meghan McDonald said.

All four of the wounded students are expected to recover, and Houpt is due to graduate this month, university Chancellor Phil Dubois said.

Campus commencement ceremonies will go on as scheduled next week, he said.

Final exams have been postponed, and the school will consider allowing professors to cancel them, Dubois said.

REUTERS