SUTHERLAND SPRINGS, Texas – The shooting at the First Baptist Church in Sutherland Springs that left 26 dead and more than 20 wounded Sunday morning was related to a “domestic situation,” officials said at a press conference Monday.

Devin Patrick Kelley, 26, of New Braunfels, has been identified as the shooter. Officials said he and his mother-in-law had a tumultuous relationship and said Kelley sent her a series of threatening text messages in days prior to the shooting. Kelley’s in-laws were members of the church but were not there at the time of the shooting.

Officials said the mass shooting was not racially or religiously motivated.

Who was Devin Patrick Kelley? Here's what we know about him

The church is located in the 500 block of 4th Street in the small, south Texas town about 40 miles east of San Antonio.

Here's everything we know about the Sutherland Springs church shooting

Kelley was found dead of a self-inflicted gunshot wound following the shooting. His body was recovered about 10 miles away in Guadalupe County from inside the vehicle that he used to flee the scene of the shooting.

Officials said Kelley walked into the church around 11:20 a.m. Sunday and began shooting. He was armed with a Ruger AR 556 assault rifle, and dressed in black tactical gear and was wearing a ballistic vest. Officials later recovered two handguns from his vehicle, a Glock 9mm and a Ruger .22 pistol. Two of the guns were bought from an Academy Sports & Outdoors in San Antonio. Officials said he did not have a license to carry guns.

Officials said Monday evening that they've collected hundreds of shell casings and 15 magazines that hold 30 rounds each.

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Among the 26 dead inside the church, ages range from just 18 months old to 77 years old. None of their names have been released officially, however First Baptist Church Pastor Frank Pomeroy said his 14-year-old daughter Annabelle Renee Pomeroy is among the deceased. Nick Uhlig told The Associated Press that his cousin Crystal Holcombe and her in-laws Karla and Bryan Holcombe died in Sunday’s attack.

The victims are being autopsied at the Bexar County Medical Examiner’s Office. Officials said their names will be released when their next of kin has been notified.

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Officials said of the 20 people inside the church who were wounded in the shooting, six are in stable condition, or have been released from the hospital, four are in serious condition and 10 are in critical condition. They are all being treated at San Antonio-area hospitals, including Brooke Army Medical Center and University Hospital.

A commanding general at BAMC says they received eight patients from the scene — six adults and two minors — all with “critical, significant, life-changing injuries.” He said seven of the patients arrived via ambulance and one was flown in a medical helicopter.

Reactions pour in following mass shooting at church in Sutherland Springs, Texas

Of the nine patients brought to University Hospital’s Level I trauma center, three children and three adults remain, a hospital spokesman said Monday morning. Their conditions range from serious to critical. Two adults were treated and released. One pediatric patient died.

Officials said after opening fire inside the church, Kelley was confronted by someone who lived near the church and gunfire was exchanged. Texas Department of Public Safety Regional Director Freeman Martin said Kelley was shot in his leg and torso by that person prior to getting into his vehicle to flee.

A look inside Sutherland Springs' First Baptist Church before mass shooting

The neighbor and another man from the Sutherland Springs community pursued Kelley for nearly a dozen miles before Kelley’s vehicle crashed. Kelley called his father while he was being chased and told him he had been shot and “didn’t think he was going to make it,” officials said at Monday’s press conference.

Who is Devin Patrick Kelley?

Kelley was previously a U.S. Air Force member who served in Logistics Readiness at Holloman Air Force Base in New Mexico from 2010 until his discharge in 2014. An Air Force spokesperson said he was court-martialed in 2012 for two counts of Article 128 UCMJ, Assault on his spouse and assault on their child. He received a bad conduct discharge, confinement for twelve months and a reduction to the grade of E-1. Officials said he had previously been charged with misdemeanor animal cruelty in east-central Colorado.

Court records in El Paso County indicate Devin Patrick Kelley was cited on Aug. 1, 2014, when he lived in a mobile home park near Colorado Springs. He was given a deferred probationary sentence and was ordered to pay $368 in restitution. The charge was dismissed in March 2016 after Kelley completed his sentence.

The Denver Post reports court records indicate someone was granted a protection order against Kelley on Jan. 15, 2015, also in El Paso County.

A statement issued by Schlitterbahn water park in New Braunfels said Kelley worked for the resort as an unarmed, night security guard for five and a half weeks during the summer before his employment was terminated. The statement indicated that all security guards must pass a criminal background check through the Texas Department of Public Safety.

Sutherland Springs shooter was fired from seasonal security guard job at Schlitterbahn

Claudia Varjabedian is a manager at the Summit Vacation Resort in New Braunfels. She told The Associated Press on Monday that Devin Patrick Kelley had been working there the past month and a half.

She says Kelley "seemed like a nice guy" and didn't give her any problems. She said he worked unarmed on his shift as the day security guard.

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This is a developing story. Stay with KSAT 12 and KSAT.com for more information as it becomes available.