Kelley, who was reportedly married, had recently posted a photo of an AR-15 style gun on his Facebook page with the caption: "She's a bad b***h."
A LinkedIn account which appears to be Kelley's states that he joined the US Air Force after graduating New Braunfels High School in 2009. He worked in logistics and supply in the Air Force until 2013, when he left and volunteered as a teacher for Bible studies at Kingsville First Baptist Church.
Wilson County Commissioner Albert Gamez Jr told CNN that at least 26 people have been killed in the shooting, but the death toll is expected to climb.
"My heart is broken," Gamez said. "We never think where it can happen, and it does happen. It doesn't matter where you're at. In a small community, real quiet and everything, and look at this, what can happen."
At least 24 others were injured in the horrific shooting, including a six-year-old boy - named only as Rylan - who was shot four times and is currently undergoing emergency surgery in hospital.
It is believed to have been the worst shooting at a place of worship in American history.
Witnesses said a man 'in full gear' walked inside the church and opened fire just before 11.30am.
First Baptist Church Pastor Frank Pomeroy told ABC that his 14-year-old daughter is among the dead. She 'was one very beautiful, special child,' the pastor said. His wife, Sherri Pomeroy, said her husband was out of town at the time of the shooting.
A young man standing outside the Brooke Army Medical Center told MySA.com that he had been wounded in the shooting and that this father had been killed. His mother was in another hospital.
Amanda Mosel's 13-year-old goddaughter was gunned down in the shooting. With tears in her eyes, the 34-year-old stood outside the Sutherland Springs Community Building where citizens gathered following the shooting.
A woman wrote on Facebook that she saw the man flee the scene in his vehicle before crashing it not far from her daughter's house. She said he then ran on foot and was pursued by police.
The suspect is dead and there is no longer an active shooter threat, according to police.
San Antonio Police Department reportedly sent in their bomb squad to investigate an SUV abandoned in Guadalupe County, near Sutherland Springs, which is believed to have belonged to the shooter, News 4 San Antonio reports.
The department is also sending a unit to the suspect's home although it's not yet clear where that is.
Police could not give an exact number of victims shot in the attack, but witnesses said they heard as many as 20 shots fired. It appears that almost everyone in the church during the service was shot.
Dana Fletcher, who owns a store in Sutherland Springs, told CNN: "It's just awful...there were emergency responders everywhere."
Neighbors in the area said they may have heard the shooter reload multiple times. Another witness at the scene said a two-year-old was also shot in the attack.
Sutherland Springs is a rural community in Wilson County, Texas, that's made up of about 400 people. It's located about 30 miles southeast of San Antonio. There are 11 hotels in the area, and there used to be a 52-floor facility, but it closed in 1923.
Some residents fear that the gunman is someone they know becuase their community is so small, but Texas Congressman Vicente Gonzalez said "apparently the shooter was not from the area, he was from outside of that area".
Gonzalez told MSNBC that officials said they "won't have final numbers until probably a few more hours".
He said that based on what he knew, he did not believe the incident was related to terrorism, but "was some kind of other incident that has to do with the church or the community".
Carrie Matula, who works at a gas station near the church, told MSNBC that she heard 'semiautomatic gunfire' and looked to see what was going on.
"I never thought it would happen here,' Matula said. 'This is something that happens in a big city. I would never have thought this would have taken place here. It's just too tight a community. It doesn't make sense."
President Donald Trump sent his condolences to the Sutherland Springs community. He also said he will continue to monitor the situation from Japan.
"God bless the people of Sutherland Springs, TX. Our country's hearts are breaking for the victims & their families. We love & are with you!" Ivanka Trump tweeted after learning of the shooting.
Texas Governor Greg Abbott released a statement following the shooting.
"While the details of this horrific act are still under investigation, Cecilia and I want to send our sincerest thoughts and prayers to all those who have been affected by this evil act.
"I want to thank law enforcement for their response and ask that all Texans pray for the Sutherland Springs community during this time of mourning and loss."
Texas Attorney General Ken Paxton said in a statement: "The thoughts and prayers of all Texans are with the people of Sutherland Springs as tragic reports come out of First Baptist Church."
'Please join Angela and me as we pray for those impacted by this horrific shooting,' Paxton said.
Texas Sen Ted Cruz tweeted: "Keeping all harmed in Sutherland Springs in our prayers and grateful for our brave first responders on the scene."
Photos show families tearfully praying outside their community building as they wait to see if their family and friends are safe.
There were at least six helicopters called in to transport victims to the hospital.
Megan Posey, a spokeswoman for Connally Memorial Medical Center, which is in Floresville and about 10 miles from the church, said "multiple" victims were being treated for gunshot wounds.
She declined to give a specific number but said it was less than a dozen. Some victims were taken by medical helicopter to the Brooke Army Medical Center.
The University Health System also said in a tweet that their 'trauma team is caring for nine of the patients from the Sutherland Springs shooting, 4 children, 5 adults, + 1 more patient on the way'.
Special agents from ATF's Houston Field Division, San Antonio Field Office are on the scene along with the FBI.
