President Jim Ryan told a Monday morning news conference the shooting happened Sunday night on a school bus of students returning from an off-campus trip.
The suspect has been identified as Christopher Darnell Jones Jr., who is also student.
The incident occurred Sunday near a university parking garage. In addition to the three football players killed, two others were reported to have been wounded.
Police went on a manhunt Monday in search of the student suspected in the attack, officials said.
During a press conference in the 11 o'clock hour local time, the university police chief, Tim Longo, was given word that the suspect was in custody. He immediately returned to the microphone and reported that update to the assembled reporters.