EAST LANSING – A man suspected of killing three people and injuring five others in a mass shooting at Michigan State University was found dead of a self-inflicted gunshot after a confrontation with law enforcement in north Lansing, police said early Tuesday.

Some of the five victims who were hospitalized had life-threatening injuries. All were in critical condition, a Sparrow Hospital spokesperson said.

The shooting began around 8:18 p.m. Monday in Berkey Hall on the northern boundary of the campus, near Grand River Avenue, the main artery through downtown East Lansing. The building is home to the College of Social Science, the Institute for Public Policy and Social Research and the Department of Sociology.

After opening fire in a Berkey Hall classroom, the 43-year-old shooter — who had no affiliation with the university — continued the attack at the MSU Union, about a third of a mile to the west, according to the schools' Department of Police and Public Safety. Two victims were killed at Berkey, one at the MSU Union.

"We have no idea why he came to campus to do this tonight. That is part of our ongoing investigation," said Chris Rozman, MSU's interim deputy police chief.

Following a more than three-hour manhunt during which terrified students and others sheltered in place and a surveillance photo of the unnamed suspect was made public, he was reported dead about 5 miles away shortly before midnight. The circumstances of the confrontation with police were not immediately released.

"This truly has been a nightmare that we are living tonight," Rozman said. "But we have remained laser-focused on the safety of our campus, our students and the surrounding community. We are relieved to no longer have an active threat on campus, while we realize that there is so much healing that will need to take place after this."

All campus activities were halted for 48 hours. Counseling services will be available.