Police officers walked amid the burned out ruins of a Church of Jesus Christ of Latter-day Saints church in Michigan on Monday, a day after a former Marine opened fire during a crowded service, killing at least four people, then set the building ablaze.

Eight others were wounded in the attack and authorities have said they are searching for more victims.

A silver pickup truck remained where it had smashed through the brick wall of the church before the gunman got out and started shooting.

It happened in a community outside Flint. The attacker was identified as Thomas Jacob Sanford, who served in the Marines and was from a nearby town.