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Authorities say the former University of Central Florida student who plotted a mass murder at the college before killing himself was keeping a checklist of things to do, and last on that list was the task, "good luck & give them hell!"

James Oliver Seevakumaran was crossing items off his list ahead of his planned attack on classmates with guns and homemade explosives, University of Central Florida Police Chief Richard Beary said Tuesday at a news conference.

The list found along with his body early Monday included such other tasks as drinking at a bar near campus and pulling the fire alarm -- which investigators suspect was meant to flush out potential victims.

Instead, Seevakumaran shot and killed himself as police officers arrived in response to the fire alarm and a 911 call from a roommate. No one else was hurt. Beary says authorities confirmed he had gone earlier to the bar and drank..

Authorities found a cache of firearms and four homemade explosives in Seevakumaran's dorm room, including an assault rifle, handgun, high capacity ammunition drums and hundreds of bullets.

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Police say Seevakumaran also had two packages waiting for him at the campus mailroom that contained two 22-round magazines, a sling for his rifle and a training DVD on proper shooting.

The police released a video of officers' response to the scene that shows several of them cautiously entering the suite with their guns drawn as strobes from the fire alarm flash. The footage shows them entering the room and discovering his body.

Beary said authorities still aren't aware of a motive or significant circumstance that led Seevakumaran to plan for an attack. The chief said they haven't found a written explanation.

The business major, who held a job at an on-campus sushi restaurant, had never been seen by university counselors and had no disciplinary problems with other students, said university spokesman Grant Heston. Heston said that the school had been in the process of removing Seevakumaran from the dormitory because he hadn't enrolled for the current semester. He had attended the university from 2010 through the fall semester.

The Associated Press contributed to this report.