ORLANDO, Fla. -

A University of Central Florida drop-out planned an attack on campus but committed suicide in a dorm before carrying it out, authorities said Monday.

Materials found in his dorm room made it appear that 30-year-old James Oliver Seevakumaran planned a wider attack, authorities said a news conference.

Seevakumaran pulled a gun on another student, who then called police, said University of Central Florida Police Chief Richard Beary. He then killed himself with a shot to the head moments later as police officers were responding to the call.

"His timeline got off," Beary said. "We think the rapid response of law enforcement may have changed his ability to think quickly on his feet."

UCF spokesman Grant Heston said the university was in the process of removing Seevakumaran from the dorm before Monday. Four makeshift explosive devices were found in a back pack, and Beary said he believes that Seevakumaran pulled a fire alarm in the dorm to get other students out in the open for an attack.

Seevakumaran's roommates told detectives that he had shown anti-social behavior but had never expressed any violent tendencies, Beary said.

According to Florida records, his only adult arrest in the state was in 2006 for driving with a suspended license. He pleaded no contest. He was fined $105 and assigned court costs of $223.

University police were called to the Tower I building around 12:20 a.m. after the fire alarm went off. Around the same time, the 911 call came in about a man with a gun.

Investigators said they discovered two guns and the makeshift explosives in the room where Seevakumaran was found dead.

About 500 students were evacuated from the building and morning classes were cancelled.

Classes on the UCF's main campus resumed Monday afternoon, 12 hours after police found a man's body, weapons and homemade explosive devices and evacuated a seven-story dormitory.

College authorities described the death as an apparent self-inflicted gunshot wound to a student, adding the school was under no immediate threat.

Heston said the dorm has suites, with a main kitchen and living area, along with four bedrooms. The dead man was inside one of the rooms. Inside the room, Heston said, police also found what they described as an assault weapon, a handgun and incendiary devices. Florida law prohibits the possession of guns on state university campuses.

"Obviously you never want somebody to commit suicide, but knowing what we know about what was in his room, we feel better at least that no one else was hurt," Heston said.

He said the Orange County Sheriff's Office and the FBI are helping with the investigation. The sheriff's bomb squad was examining the explosive devices Monday morning, and the makeshift devices were taken away from the dorm.

All students were evacuated from the dorm, and Heston said it remained closed until authorities gave an all-clear on the building.

Flashing signs around the campus alerted students and staff about the cancelled classes. Campus shuttle buses were lined up about a half-mile from campus, with drivers standing by once the campus opens. The university's main campus in Orlando has about 51,000 students.

Antonio Whitehead, 21, a junior from Hollywood, Fla., said he heard the fire alarm go off after midnight and thought it was a routine alarm. He headed outside where he saw a crowd already heading across the street from the dorm.

"All of a sudden, I felt the crowd move a little faster. And a police officer with a machine gun or something told everyone to start moving a lot faster," he said.

Whitehead, who has lived in the dorm for two years, said the students were moved to an open area about 1,000 feet from UCF Arena. The area is a busy section of the campus, with restaurants and shops nearby.