A second officer was suspended Wednesday after a video surfaced showing police in riot gearing beating a University of Maryland student during a rowdy celebration following a big basketball win.

Prince George's County Maj. Andy Ellis said at least two more officers could be suspended. He said the first one suspended was Sean McAleavey, who filed charging documents against two students, including 21-year-old John McKenna, who was beaten in the March 3 video. Those charges were dropped.

Ellis said police have identified all the officers involved. Some came forward on their own and the rest were confirmed by investigators. He said he understands the public's concern, but he could not yet name the officers.

"We're being very deliberate as we move forward," he said.

Police are concerned about the officers' safety because the department has received numerous hostile and threatening phone calls from across the country from people angered at the beating and police, Ellis said.

The video, taken by a student from a dorm room window, shows a crowd in the street celebrating Maryland's 79-72 victory over Duke. McKenna half-jogs, half-dances down the sidewalk. He stops when he sees a pair of officers on horseback in front of him and they corner him.

Suddenly, three officers in riot gear run toward him, slam him into a wall and beat him with batons. In the video, the beating appears unprovoked.

No listed phone number for McAleavey could be found.

Ellis said police had their first meeting on Wednesday with the FBI, which is reviewing the video and the events of that night. The Justice Department said once the FBI review is complete, it will determine if civil rights law were violated.

Ellis said the use of force that night was already being looked at before the video surfaced. Police are evaluating their procedures and policies, including how quickly to deploy officers in such circumstances, he said.

McKenna's attorney, Christopher A. Griffiths, released the video on Monday. Prosecutors have dropped assault charges against McKenna and Benjamin Donat, who were accused of screaming in the street and causing a crowd to form on the sidewalk that became unruly. They were among 28 people arrested that night near the College Park campus.

The charging documents don't reflect the series of events depicted in the video. Ellis said the documents were in error, and police are looking into whether officers mistakenly transcribed the scenario from another arrest, or if the charging statements were fabricated.

In his first public statement since the video came out, University of Maryland President C.D. Mote Jr. said the events after the game raise concerns and require a thorough investigation. Mote praised police for moving forward and said he appreciated the involvement of state and federal authorities.

"I am confident that the investigation will clarify what happened that night and how we can prevent such incidents in the future," Mote said.