(CNN) -- The man who killed 26 people inside a small Texas church on Sunday was armed with an assault rifle, 15 loaded magazines and an obsession with a family dispute.
As investigators try to piece together a picture of Devin Patrick Kelley, more clues have emerged in the deadliest shooting in Texas history. The dead parishioners from the First Baptist Church in Sutherland Springs ranged in age from 17 months to 77 years old, and included an unborn child.
Kelley, who had a record of violence, appeared to be consumed by a dispute with his mother-in-law and spent time posting anti-God and pro-gun statements on Facebook in the months before the shooting, according to officials, as well as acquaintances and former classmates.
He sent threatening text messages to his mother-in-law and texted her as recently as Sunday morning -- not long before he sprayed bullets at the people in the church with an assault rifle, authorities said.
"There are many ways that he could have taken care of the mother-in-law without coming with 15 loaded magazines and an assault rifle to a church," Freeman Martin of the Texas Department of Public Safety said. "I think he came here with a purpose and a mission."
- The FBI now has the shooter's cell phone, but has not yet accessed its content due to encryption -- a growing challenge for law enforcement, Christopher Combs, FBI special agent in charge, said at a Tuesday news conference.
- The 26 fatalities include an unborn child, according to Martin.
- As of Tuesday, 10 of the wounded remained in critical condition, Martin said.
- In an October 29 Facebook post, Kelley posted a photo of a Ruger AR-556 rifle -- the same type used in the shooting -- on a white couch, former classmates and members of the community told CNN. The caption read, "She's a bad bitch." It's not clear if it was the same weapon he used on Sunday.
- The US Air Force acknowledged it did not relay information about Kelley's court martial conviction for domestic assault to civilian law enforcement, something that could have prevented him from purchasing the firearms used in the shooting. The Air Force and Department of Defense are investigating how records of his domestic violence conviction were handled.
- Kelley, 26, had three gunshot wounds. He was shot in the leg and torso by an armed citizen, and had a self-inflicted shot to the head, authorities said. It wasn't clear which gunshot killed Kelley, but there's evidence at the scene "that indicates the subject may have died from a self-inflicted gunshot wound," Martin said. He was found dead in his vehicle.
- Investigators have reviewed video footage from inside the church, Martin said.
- Kelley was denied a license to carry a gun in Texas, Gov. Greg Abbott said. But he passed a background check required for the purchase he made in April 2016 of the Ruger AR-556 rifle he is believed to have used in the shooting.
Learning more about the shooter
Officials had said there was a domestic situation involving Kelley, but didn't go into any details.
"This was not racially motivated. It wasn't over religious beliefs. There was a domestic situation going on with the family and in-laws," said Christopher Combs, the special agent in charge of the FBI's San Antonio division.
Kelley had also expressed anger toward his mother-in-law, who attended the church, Martin said. She was not at the church Sunday.
But his grandmother-in-law was killed during the attack, multiple friends of the woman told CNN. Lula White was the grandmother of Kelley's wife and often volunteered at the church, according to friends and her Facebook profile.
Public records -- and those who knew Kelley -- describe a troubling history.
Christopher Leo Longoria went to high school with Kelley. He said his former classmate would focus on women's reactions and that it would "creep out the ladies." Longoria said he had recently unfriended him on Facebook because Kelley was launching into online personal attacks against his friends.
"He was also posting a lot of non-God beliefs, atheism, a lot of gun violence and a lot of weapons that he was into," Longoria told CNN's Don Lemon.
Longoria described Kelly's Facebook posts as "a ridiculous amount of nonsense." Kelly's page was taken down Sunday but people in the community have confirmed its existence and content.
His social media suggested a fascination with mass shootings, said a law enforcement official.
Kelley had served at the Holloman Air Force Base in New Mexico beginning in 2010, but was discharged in 2014. After being court-martialed in 2012 for assault on his spouse and child, he served a year in military prison and received a bad conduct discharge, according to Air Force spokeswoman Ann Stefanek.
Kelley was involved in "multiple occasions of domestic abuse" against his ex-wife and stepson, said Don Christensen, the former Air Force chief prosecutor when Kelley was sentenced.
He said Kelley "violently" shook the child, causing fractures in his skull and a subdural hematoma -- a severe head injury in which there's bleeding between the skull and the brain.
Kelley "admitted to, out of anger, pushing his son down and injuring him," Christensen said.
In addition to abuse of his spouse and stepson, Kelley had been arrested in August 2014 on an animal cruelty charge in El Paso County, Colorado, after a witness said he had punched a dog, grabbed it by the neck and dragged the animal. Kelley denied the account and was issued a summons but didn't spend any time in jail.
'Most of our church family is gone'
Authorities said 4% of the small town's population was killed in the shooting. As of Tuesday morning, 12 victims remained hospitalized.
The church's visiting pastor was among the dead, Wilson County Sheriff Joe Tackitt said. A family member identified the visiting pastor as Bryan Holcombe.
In all, eight members of the Holcombe family spanning three generations -- including a pregnant woman and three of her children -- were killed, said Ron Scott, the visiting pastor's first cousin.
Standing outside the family farm in Floresville, Texas, Scott Holcombe tearfully spoke about his deceased parents, Bryan and Karla Holcombe, and the rest of the family members lost in the shooting.
He said he had met the gunman and was confident Kelley would have known and spoken to every single person in that church community.
Kelley emptied 15 magazines -- about 450 rounds -- at the First Baptist Church, leaving such extensive destruction that the pastor's wife, Sherri Pomeroy, said: "Most of our church family is gone, our building is probably beyond repair."
As Kelley left the church, he was confronted by Stephen Willeford, who lives near the church and ran out of his house barefoot with his gun when he heard the shots. Kelley was shot twice by Willeford, law enforcement said. Then Kelley fled in a car, chased by Willeford and another man, Johnnie Langendorff.
After Kelley was shot, he called his father, telling him he didn't think he was going to make it, Martin said. That's when Kelley shot himself.
The chase ended with his car in a ditch and the gunman dead in his vehicle.
The pastor, Frank Pomeroy and his wife had been out of state when the shooting occurred, but their 14-year-old daughter, Annabelle Pomeroy, was killed in the attack.
In an emotional news conference on Monday, the pastor said: "I don't understand, but I know my God does."
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