MONROE, Mich. (AP) — Police say an explosion in southeastern Michigan that's being investigated as the detonation of a car bomb seriously injured three people inside the vehicle.

The Monroe Police Department said in a statement that fire crews responded to the explosion about 5:40 p.m. Tuesday in Monroe near Interstate 75. Police say the three inside the vehicle were taken St. Vincent Medical Center in Toledo, Ohio, where they were in serious condition.

A charred shell was all that remained of the vehicle, according to video shown by Detroit-area TV stations.

Police say the investigation was in its early stages in Monroe, located about 35 miles southwest of Detroit and 20 miles northeast of Toldeo.

The department says the Bureau of Alcohol, Tobacco, Firearms and Explosives and Michigan State Police also were investigating.