A veteran of the US Marine Corps, who had American flags displayed on his pickup truck, crashed into a Michigan Church of Jesus Christ of Latter-day Saints on a Sunday morning, igniting a fire and opening fire on hundreds of churchgoers.

In the aftermath, at least four church members lost their lives and eight sustained injuries. The attacker, 40-year-old Thomas Jacob Sanford, was fatally shot by police in the church’s parking area, reported the Detroit Free Press.

Blanc Township Police Chief William Renye detailed that one church member succumbed to gunshot wounds on site, while another passed away later on Sunday at Ford Genesys Hospital. By Sunday evening, Renye confirmed the discovery and identification of two more church members’ remains from the smoldering remains of the church building.

More bodies may be found in the rubble.

“We’re diligently searching for more bodies,” he stated. “Due to the church being a complete loss from the fire, we haven’t fully examined the site… I’m unsure of how many people remain unaccounted for at this moment.”

The FBI said it was leading the investigation into what acting special agent in charge Reuben Coleman called “an act of targeted violence.”

According to James Dier from the Bureau of Alcohol, Tobacco, Firearms and Explosives, Sanford ignited the fire with gasoline and was in possession of explosive devices, as reported by The Associated Press. Dier mentioned it was uncertain if these explosives had been used.

ABC News revealed that Sanford served in the Marine Corps from June 2004 to June 2008, achieving the rank of sergeant and receiving commendations for his service, including a tour in Iraq. He was also a father to a son who, according to the network, “faced significant health challenges since birth.”

He was from the town of Burton, about six miles from Blanc Township, NBC News reported. Both towns are suburbs of Flint. Images posted by family online showed him wearing Trump regalia. Other images show he was a frequent hunter.

Unlike several previous shootings, federal authorities have not immediately suggested that Sanford’s political views played a part in his murderous rampage. Friends, however, indicated he may have suffered from PTSD.