At least four people were killed after a gunman attacked a Church of Jesus Christ of Latter-day Saints in Grand Blanc Township, Mich., on Sunday.

The attack occurred when a man drove a car into the church building, set fire to it and shot worshipers, the authorities said. Eight other people were wounded, one of whom was in critical condition.

The gunman died after a confrontation with officers. Investigators had not yet determined a motive.

Here’s what we know.

What happened?

The attack began just before 10:30 a.m., at a Church of Jesus Christ of Latter-day Saints branch in Grand Blanc Township, Mich., a suburb of about 8,000 people near Flint.

The gunman crashed a vehicle into the building, then began shooting at congregants who were attending Sunday services, the police said. Fire soon consumed the church, as well.

Officers responded within a minute to reports of the shooting. Eight minutes later, the shooter was dead after exchanging gunfire with the police, the authorities said.

Investigators believe the fire was fueled by gasoline or another accelerant. Three makeshift explosives were also recovered, said James Deir, an agent with the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Who is the suspect?

The gunman was identified by the authorities as Thomas Jacob Sanford, 40, of nearby Burton, Mich. Mr. Sanford, who also went by Jake, used an assault-style rifle in the shooting, the authorities said.

He graduated from a nearby high school in 2004 and then enlisted in the Marines, serving four years, including a deployment to Iraq in 2007.

Neighbors described him as quiet, even generous. One recalled how he plowed driveways in winter for free.

He married a woman in 2016, court records show, and the couple had a 10-year-old son.

What church was attacked?

The congregation in Grand Blanc Township is part of the Church of Jesus Christ of Latter-day Saints, or Mormon Church, based in Salt Lake City, Utah, which counts millions of members worldwide. Its longtime president, Russell M. Nelson, died on Saturday, at 101.

The Grand Blanc Township church was “one of the largest” in the area and steadily growing, with “around 150 members,” according to Justin Jensen, a 19-year-old Latter-day Saint missionary in the area.

Each Sunday, congregants gather for two hours of worship, starting in the chapel, with attendees seated in pews, singing from green hymnals. The attack came during the first hour.

The church building was declared “a total loss” because of the fire, said Chief William Renye of the Grand Blanc Township Police Department.

What is the status of the investigation?

The F.B.I. has opened an inquiry, calling the attack “an act of targeted violence.” Officials are still trying to determine a motive.

Federal agents and emergency responders were at the scene combing through the blackened wreckage of the church late into Sunday night. The authorities have not yet released the names of any victims. Chief Renye said he believed that more victims would be found the rubble.

Mr. Deir, of the Bureau of Alcohol, Tobacco, Firearms and Explosives, said the gunman might have planned to ignite a fire with the makeshift explosive devices, and added that it was unclear if a similar device had been used to start the fire at the church.

The Michigan attack adds to a growing list of recent assaults on American religious institutions. Two children were killed by an assailant at a Catholic school in Minneapolis in August. In July, two women were fatally shot and two others were wounded on the grounds of a church in Lexington, Ky.