By Gabriella Borter and Brendan O’Brien

(Reuters) – 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.

‘I SHOT THE GUY’

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, a spokeswoman for the local prosecutor said. First-degree murder in North Carolina carries a mandatory minimum sentence of life in prison without parole, and a conviction would make Terrell 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.

MEMORIAL ASSEMBLY

The shooting started in a classroom at about 5:40 p.m. on Tuesday, the last day of classes, police said. Tristan Field, a student who witnessed the violence, told CBS News as many as 50 classmates tried to flee through two doors.

“A chair fell in front of the door, so people were tripping over that, like, trying to climb over it,” he said. “Some people fell down. It was like water through a funnel but wasn’t fast enough.”

Several thousand students, faculty and others – many wearing green T-shirts emblazoned with the school’s “49ers” nickname – filled the campus sports arena to capacity on Wednesday evening for a student-organized memorial honoring the shooting victims.

Addressing the grieving assembly, including Governor Roy Cooper and other state and local civil leaders, Dubois drew thunderous applause as he hailed the heroism of police and Howell in confronting the gunman.

“We are heartsick that anyone would act with such disregard for human life,” he said, lamenting that nothing could bring back the lives lost. “But with your help we will find a way to remember their presence.”

The campus, located in the heart of North Carolina’s largest city, has about 30,000 students enrolled and employs some 5,000 faculty and staff.

The deadliest mass shooting on a U.S. college campus took place at Virginia Tech University in Blacksburg, Virginia, in April 2007, when a student killed 32 people, then himself.

(Reporting by Gabriella Borter in New York Brendan O’Brien in Milwaukee and Alex Dobuzinskis and Steve Gorman in Los Angeles; Writing by Scott Malone, Editing by Bill Tarrant, Bill Trott and Chris Reese)