This is a developing story. Check back for updates.

A man responsible for opening fire on a community church in Sutherland Springs, Texas died after the attack, law enforcement said. Devin Kelley, 26, of New Braunfels, Texas was identified as the alleged attacker and was believed to be the sole person responsible, according to the Associated Press. Initial reports suggested Kelley was killed by police, though investigators said Sunday evening it remained unclear whether he died of a self-inflicted gunshot wound or was shot by someone else.

Texas Gov. Greg Abbott confirmed in a press conference that at least 26 people were killed, though it remained unknown whether that number would go up in the coming days and hours. The ages of those killed ranged from 5 to 72-years-old. The 14-year-old daughter of the church’s pastor was also killed in the attack, according to Fox News.

Kelley reportedly entered the First Baptist Church in Sutherland Springs, a town about 30 miles southeast of San Antonio, and began shooting Sunday afternoon. He was apparently dressed in all black tactical gear and wore a ballistic vest. No motive had yet been ascertained in the shooting, Wilson County Sheriff Joe Tackett told NBC News. Kelley reportedly lived in a suburb of San Antonio and did not appear to be linked to any organized terrorist groups, an official told the AP.

“Apparently the shooter was not from the area, he was from outside of that area,” Texas Congressman Vincente Gonzalez told MSNBC.

Kelley was reportedly a former United States Air Force service member, who received a dishonorable discharge and was court-martialed in 2014, CBS News reported. Investigators said they were looking into Kelley’s alleged social media posts, including one that may have shown an AR-15 semiautomatic weapon.

“I talked to one of gunman Devin Kelly’s Facebook friends, who says Kelley was randomly adding strangers and starting fights on Facebook,” Los Angeles Times correspondent Matt Pearce tweeted.

Bystanders described to reporters hearing the shooting take place from places nearby the church.

“[The shooting] lasted about 15 seconds,” Carrie Matula, a resident who was working at a gas station across the street from the church at the time of the shooting, told WPLG. “I yelled ‘Get down! Get inside! And we all went into hiding.”

Officials said in a press conference Sunday evening that after the attack was underway, a next-door neighbor engaged with the gunman, firing shots from his own rifle and chasing him away from the scene. The unidentified citizen also pursued the suspect and caused him to drop his gun, officials said.

The FBI and Bureau of Alcohol, Tobacco, Firearms and Explosives were assisting in the aftermath of the shooting, according to the Associated Press.

“May God be w/ the people of Sutherland Springs, Texas,” President Donald Trump tweeted. “The FBI & law enforcement are on the scene. I am monitoring the situation from Japan.”