DEARBORN HEIGHTS, Mich. (AP) — A private court security officer fatally shot a man who was brandishing a knife and tried to bypass security at a police department and court complex in suburban Detroit Thursday, authorities said.

Officers responded after a shooting was reported at the Dearborn Heights Police Department and 20th District Court complex.

The confrontation started around 8:45 a.m. after the man tried to get into the courthouse by bypassing security and confronted a security officer with a weapon, state police Lt. Michael Shaw told reporters at a news conference. He was killed in the lobby, Shaw said.

During the late-morning briefing, Shaw declined to release any other details.

"We believe he was alone," Shaw said.

Dearborn Heights Mayor Dan Paletko, who also was at the news conference, earlier told TV stations WXYZ and WJBK that the man had a knife and that he was fatally shot after lunging at a security officer at a security check station. Police at the scene gave WWJ-AM a similar account.

Paletko didn’t elaborate on details of what happened, but said area schools were placed on lockdown. The courthouse also was closed for the rest of the day.

Edward Mandell, 53, of Dearborn Heights, told the Detroit Free Press that he rushed to the scene after his wife called, whispering that there had been a shooting. He said she works in the records department and is OK but heard the shots being fired.

State police took over the investigation at the request of Dearborn Heights police, Shaw said, and kept witnesses in the building for interviews. Shaw said investigators believe there’s no threat to the public and that they were trying to determine why the person killed was at the courthouse.

Dearborn Heights resident Sherry Matthews, 64, arrived at the building just before 9 a.m. to accompany a friend to court. She told The Detroit News that she saw officers with large, assault-type weapons and that they let some people out of the building.

"When I pulled up to the parking lot, all the entrances and exits were blocked," she said. "The only people I saw go in were three officers who pulled up and went running into the building with their guns drawn."

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