The gunman suspected of opening fire at a church in Texas on Sunday has been identified to Fox News 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.

JUST IN: This is a photo of Texas shooting suspect 26-year-old Devin Patrick Kelley, CBS News confirms https://t.co/ll0ZgUQFFy pic.twitter.com/JfEuYqmy7l

— CBS News (@CBSNews) November 6, 2017

The gunman previously served in the U.S. Air Force, an Air Force spokesperson confirmed to Fox News. Kelley served at Holloman Air Force Base in New Mexico from 2010 until his discharge in 2014.

He was court-martialed in 2012 for assaulting his wife and his child. Kelley received a bad conduct discharge from the Air Force, in addition to confinement for 12 months and was reduced in rank.

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, a suburb outside San Antonio, was found dead in his car after he sped away from the scene of the shooting. Officials said it remained unclear whether he was shot dead by police or an armed nearby resident, or if he died from a self-inflicted wound.

Police didn’t name Kelley during a press conference, but only described him as a white male in his 20s.

Kelley was dressed in black tactical gear and wearing a ballistic vest when he arrived at a Valero gas station near the First Baptist Church around 11:20 a.m., investigators said.

Speaking at a news conference Sunday night, officials said he crossed the street to the church, left his vehicle and began firing a Ruger AR assault-type rifle at the place of worship. Kelley was then suspected of entering the church and firing at the crowds of people.

Investigators are looking into recent Facebook posts made by Kelley – one in particular that showed what appeared to be a semiautomatic weapon.

Kelley was married, according to The Daily Beast. His mother-in-law’s P.O. Box was listed as a mailing address in Sutherland Springs.

Fox News' Lucas Tomlinson and The Associated Press contributed to this report.