NEWAYGO, Mich. (WOOD) — There was an explosion at Newaygo High School Monday morning when a homemade device brought in by a student went off in a classroom.

Newaygo Public Schools initially said it was a firework but police later determined it was not.

Investigators said the device was detonated shortly before 9 a.m. as the 16-year-old who brought it in sat at his desk.

Michigan State Police initially said it was an accident, then told News 8 Monday afternoon that the explosive was set off intentionally, but that the student didn’t understand how big the resulting explosion would be. On Tuesday morning, MSP again stated that the bomb was set off on accident.

The 16-year-old sustained what were described as severe injuries, though police would not provide further details.

Four other students sustained minor injuries and were taken by their parents to the hospital. The teacher went to the hospital, as well. They also needed to be checked out because they may have inhaled whatever chemicals were used in the device.

Newaygo Public Schools Superintendent Peg Mathis wrote in a Facebook post that has since been deleted that the student wasn’t trying to attack anyone, but rather that he demonstrated “a serious lack of judgment.” Police agreed that the student did not mean to hurt others.

“We don’t believe it was any kind of malicious intent on behalf of the student,” MSP Spl./Lt. Michelle Robinson said during an afternoon press conference streamed live on Facebook by 9&10 News out of Cadillac.

Newaygo Police Department Chief Georgia Andres assured parents that “it was an isolated incident” and that the school was safe. She said more information would be available as the investigation progresses.

Emergency responders on the scene at Newaygo High School after a homemade explosive device brought in by a student exploded on March 8, 2021. (Courtesy 9&10 News)

Police said they were still working to determine why the student brought the device to school.

The Bureau of Alcohol, Tobacco, Firearms and Explosives was called into help determine how it was constructed. Investigators were executing a search warrant in connection to the case Monday afternoon.

Once the investigation is over, the case will be sent to the county prosecutor to determine what, if any, charges are appropriate.

Schools were locked down after the explosion, per protocol. The district sent high school students home for the remainder of Monday. Kindergartners through eighth graders had a full day as usual.