Officers at a middle school in Wisconsin shot and Christopher Caldwellkilled a gunman Monday evening after he got on the roof of the school and opened fire on police, authorities said.

An officer with the Germantown Police Department first said no injuries occurred at the Kennedy Middle School, roughly 20 miles northwest of Milwaukee, but the Wisconsin Department of Justice later issued a statement around midnight saying the suspected shooter was shot by Germantown officers shorty after 6:36 p.m.

The DOJ said aid was rendered but the man died at the scene.

Police initially responded to the school following a report of a person "acting erratically" in the parking lot. The DOJ said the man was able to climb onto the roof of the school and two officers pursued on foot.

The man discharged his firearm and officers returned fire, according to the DOJ.

The incident caused a large law enforcement response. At about 8:40 p.m. the Germantown School District released a statement saying the school was on lockdown and all students were being transported by bus to MacArthur Elementary. Parents were reunited with their children there.

The DOJ said about 50 to 70 students were inside the school at the time of the shooting.

The involved officers have been placed on administrative leave, per standard protocol.

Contributing: Christopher Cann