Who is Texas church shooter Devin Patrick Kelly?

The gunman suspected of opening fire at a church in Texas on Sunday has been identified  as 26-year-old Devin Patrick Kelley.

Kelley, according to officials, killed at least 26 people and wounded approximately 20 after he unleashed a hail of bullets in the First Baptist Church in Sutherland Springs, in the deadliest church shooting in modern U.S. history.

Authorities say Kelley had previously sent threatening text messages to his mother-in-law, who attended the church.

Texas Department of Public Safety Regional Director Freeman Martin said Monday that the mass shooting stemmed from a domestic situation and was not racially or religiously motivated.

He was discharged from the Air Force for allegedly assaulting his spouse and child, according to an Air Force spokeswoman.

The spokeswoman, Ann Stefanek, said Sunday that Devin Kelley served 12 months' confinement after a 2012 court-martial. He ultimately received a bad conduct discharge and reduction in rank.

She said Kelley served in Logistics Readiness at Holloman Air Force Base in New Mexico from 2010 until his discharge in 2014. His job responsible for moving passengers, cargo and personal property in military transportation.

Kelley worked as a security guard for a Texas waterpark this past summer, according to a resume under his name that appears online.

Investigators said Kelley didn't appear to be connected to any organized terrorist groups.

The suspect, who is believed to be from New Braunfels, outside San Antonio was found dead in his car after he sped away from the scene of the shooting. Officials believe he died from a self-inflicted wound.

Neighbors said that they heard intense gunfire coming from the direction of the address listed for Kelley in recent days.

"It's really loud. At first I thought someone was blasting," said Ryan Albers, 16, who lives across the road. "It had to be coming from somewhere pretty close. It was definitely not just a shotgun or someone hunting. It was someone using automatic weapon fire."

A person matching Kelley's name and date of birth also registered in 2014 to vote in Colorado, with an address listed in Colorado Springs, home of the U.S. Air Force Academy. 
The Colorado Secretary of State's office lists his registration now as inactive.

According to Texas Department of Public Safety regional director Freeman Martin, the gunman arrived at a Valero gas station near the First Baptist Church of Sutherland Springs at around 11:20 a.m. Sunday. He was dressed in black, wearing tactical gear and a ballistic vest.

The Associated Press contributed to this report