Chapel Hill, N.C. — As police continued to investigate a bomb threat on the University of North Carolina campus, students on Monday questioned the effectiveness of a security system designed to alert them quickly to potential threats.

An unidentified man called Orange County 911 at about 9 p.m. Sunday and said a bomb was at "The Pit," a popular gathering spot in the middle of the UNC campus. Students registered with the Alert Carolina crisis information system were notified of the threat via text message at about 11:30 p.m.

Some students questioned the delay in receiving information about the incident.

"The first Web site that had anything about (the bomb threat) was the Daily Tar Heel Web site, and that's how I was reading about it," freshman Ian Dale said. "Eventually, the Alert Carolina system online had some information about it.

"The fact that you had to learn about it through the news – a news source rather than the university – is kind of concerning," Dale said.

Sophomore Jasmine Gregory said she received a text message about the bomb threat at 11:51 p.m. Sunday.

"At the time, I mean, I wasn't on campus, but other people were there, and if they didn't know, they couldn't have done anything about it," Gregory said.

Alert Carolina was established in the wake of the April 2007 massacre of 32 students and faculty at Virginia Tech. The system is designed to send information quickly to students and staff about potential threats on campus.

UNC officials declined to discuss Monday why the text messages were sent more than two hours after the bomb threat was received. A statement posted on the Alert Carolina Web site said authorities were more concerned about evacuating the immediate area.

"The university focuses first on responding to the threat and protecting those directly at risk. Once that essential work is done, and when the facts are available, we will post information about campus security to the Alert Carolina Web site," the statement said.

The only three instances where activating the sirens and sending the text messages are the first priority if a gunman were on campus, a tornado was approaching or a hazardous chemical spill had occurred, the Alert Carolina statement said.

Sophomore Alexis Ivey disagreed with the lower priority officials gave to notifying students about the bomb threat.

"The fact that there was such a large delay, if there was an actual threat on campus, a lot of students wouldn't have been notified," Ivey said. "You kind of have to take every threat as seriously as possible."

Campus police, Chapel Hill police and Orange County sheriff's deputies responded to "The Pit" immediately after receiving the threat and evacuated surrounding buildings. Several searches of the area turned up nothing, and police allowed students to return to their dormitories early Monday.