UPDATE 5-University of North Carolina student confronted gunman, gave life -police chief

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

Environmental studies student Riley Howell of Waynesville, North Carolina, one of two students killed in the Tuesday shooting, played a key role in ending the attack, Kerr Putney, chief of the Charlotte-Mecklenburg Police Department, said at a news conference. "But for his work, the assailant may not have been disarmed," said Putney, a UNC Charlotte alumnus. "Unfortunately he gave his life in the process. His sacrifice saved lives."

The other student killed in the shooting was Ellis Parlier, 19, officials said. Four wounded students were identified as Drew Pescaro, 19; Sean DeHart, 20; Emily Houpt, 23; and Rami Alramadhan, 20. The school's chancellor, Phil Dubois, said all of the wounded were expected to recover, with one already released from the hospital.

Police in Charlotte charged UNC Charlotte student Trystan Andrew Terrell, 22, with two counts of murder and four of attempted murder but offered no explanation for a motive. Terrell is due to make an initial court appearance on Thursday, jail records show.

Students on the campus spent a harrowing night as police searched door-to-door for other suspects, not giving the all-clear until almost dawn on Wednesday. "This is the saddest day in UNC Charlotte's history," Dubois said in a letter to the community on the school's website.

The shooting started in a classroom at about 5:40 p.m. on Tuesday, police said. Tristan Field, a student who witnessed the shooting, told CBS News as many as 50 students tried to escape 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."

A vigil was planned at the school for Wednesday, CBS News reported. Sandy D'Elousa, a spokeswoman for the Charlotte-Mecklenburg Police Department, which is leading the investigation, said the gunman was believed to have acted alone.

North Carolina Governor Roy Cooper called the incident a tragedy. "But I know the people in this community, and they will be here for each other," he said at a news conference.

The University of North Carolina at Charlotte has more than 26,500 students. 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 and then himself. (Reporting by Gabriella Borter in New York and Brendan O'Brien in Milwaukee; Editing by Scott Malone and Bill Trott)