Police at Michigan State announced that all activities on campus, including athletics, have been canceled for the next 48 hours in the wake of a fatal shooting there Monday night.

Three students were killed and at least five others were wounded after the shooter opened fire shortly before 8:30 p.m. ET, according to university police. Interim Deputy Chief Chris Rozman said several victims suffered life-threatening injuries and that the five were in critical condition at Sparrow Hospital.

"This truly has been a nightmare we're living tonight," Rozman said.

Police said later Tuesday morning that the gunman, who killed himself hours after the shooting, was Anthony McRae. He was 43. McRae shot himself miles away from campus while being confronted by police.

The police also reiterated that McRae had no affiliation with the university.

"We have no idea why he came to campus to do this tonight. That is part of our ongoing investigation," Rozman said.

Police also said the five people who are in critical condition are also students.

Police had released photographs of the suspect after the shooting, describing him as a shorter Black male wearing red shoes, a jean jacket and a navy baseball cap with a light-colored brim. He remained at large for several hours.

The first shots were fired at Berkey Hall, a classroom building on the north side of campus. Shots were also fired at the MSU Union, a popular hub to eat or study, according to police. Students were ordered to shelter in place beginning at 8:30 p.m.

Rozman said two people were killed at Berkey Hall and another was killed at the MSU Union.

The Spartans' men's and women's basketball teams were off Monday night, but the men's team was scheduled to host Minnesota on Wednesday at 7 p.m. ET. The Michigan State men's tennis team was scheduled to host Drake on Wednesday at 5 p.m. ET in the only other scheduled home athletic event through the next 48 hours.

The Spartans' women's basketball team is scheduled to play at Purdue on Wednesday night, but it wasn't immediately known how that game might be impacted.

Rozman did say that the 48-hour window of cancellations is "subject to change."

Teresa Woodruff, interim university president, said it would be a time "to think and grieve and come together."

Michigan State has about 50,000 students, including 19,000 who live on campus. Names of the victims weren't immediately released by police, nor was it known whether they were Michigan State students.

Information from The Associated Press was used in this report.