In the moments after a shooting at the University of Central Arkansas, two resident advisers worked in vain to revive one of the two fatally wounded students as he gasped for air in a dormitory hallway.

"I was trying to call 911, but I was shaking too bad so I couldn't," said T.J. Frix, 18, a freshman who saw the attempt at the Arkansas Hall residence hall. "They both handled it really well. They stepped into action while everyone else" panicked.

President Tom Courtway canceled Monday's classes after Sunday night's shootings that also injured another man. Police said they've identified four suspects and that there was no continuing threat to the 12,500-student campus 30 miles north of Little Rock.

Click here for photos.

Campus police Lt. Rhonda Swindle named the dead as Ryan Henderson, 18, of Little Rock, who lived in Arkansas Hall; and Chavares Block, 19, of Dermott, a UCA student who lived off-campus. The shooting's survivor, Martrevis Norman of Blytheville, was shot in the leg but had been released from the hospital.

Police said the suspects were all male and from the central Arkansas area but were not students.

"It does not seem at this time that it was a random act," said campus police Lt. Preston Grumbles.

Swindle said three people were being questioned and that no arrests were made. One suspect was pulled over by police, and another turned himself in at the police station, authorities said. A statement from the university released late Monday afternoon said a third suspect had been detained, but did not give any other details.

The site of the shootings — an alley between Arkansas Hall and the Snow Fine Arts Center — stood mostly empty late Monday morning. One male student wept nearby, signs of blood still visible on the sidewalk.

Frix, of Russellville, said he heard five gunshots as he studied for a communication exam in his Arkansas Hall dorm room. He dismissed the noise at first.

"You don't expect to hear gunshots," he said. "I was like, 'Maybe it's just fireworks."'

But soon, the two bleeding men were in the hallway right outside Frix's dorm room. Jeremy Rucker, 20, a junior mass communication major from Little Rock, said he saw Norman hobbling around the dorm hallway, bleeding from his leg wound. Henderson lay on the floor, his chest bleeding from a gunshot wound as the sounds of his labored breathing filled the hall, Rucker said.

"He was still alive. He was struggling," Rucker said. "He was trying get air."

Henderson stopped breathing and the two resident advisers immediately began to perform CPR on him, Rucker said. Other resident advisers formed a protective ring to keep onlookers away as the two struggled to keep Henderson alive, according to Rucker.

Five minutes passed before paramedics made it to the hallway.

"They were trying their hardest to keep him alive," Rucker said.

Swindle lauded the resident advisers' quick action.

They "performed CPR at some point and did not hesitate to do so," the lieutenant told reporters at a news conference. "They stepped up to the plate and helped our officers tremendously."

The campus was quiet Monday, its sidewalks empty as a bell tower chimed on the hour. Police cruisers circled its quiet streets and uniformed officers roamed the grounds.

Students planned a candlelight vigil Monday night to remember the slain students. Block, a sophomore pre-engineering major, enrolled at the university last year. Henderson was a freshman undecided about what he wanted to major in.

Rucker called Henderson a friend and said his death came as a shock.

"He was a real quiet guy. He got along with everybody," Rucker said. "That would be the last thing I would expect to happen to him."

Sunday's shooting is the second at an Arkansas college this year. On Feb. 27, a man was shot and wounded at the University of Arkansas at Little Rock. Two suspects were charged. The victim, James Earl Matthews, was hospitalized and had surgery before being released.

Courtway said he thought police officers and the university's emergency alert system performed well in the minutes after the shooting. He promised classes would resume Tuesday and said officials would conduct a thorough examination of shooting to ensure students' safety in the future.

"This is just an awful tragedy. It's the worst thing that can happen on a college campus," Courtway said. "We have start looking at everything."