At least four people were killed and several others injured in a shooting and arson attack at a Mormon church in Grand Blanc Township, Michigan, the U.S. on Sunday.

Police said the suspect, a 40-year-old former U.S. Marine identified as Thomas Jacob Sanford, drove his vehicle into the church before opening fire with an assault rifle. He was shot dead by responding officers within minutes.

Authorities have not yet announced a motive, and several people remain unaccounted for.