Before Devin Kelley massacred churchgoers during a worship service in Texas, he claimed he bought dogs on Craigslist as "target practice" to test his weapons.
His former Air Force colleagues added that Kelley had a morbid obsession with mass shooters and fawned over guns.
Jessika Edwards, who says she worked as the suspect's supervisor at Holloman Air Force Base in New Mexico from 2010 to 2012, told CNN Kelley told her about his "target practice" when they reconnected on Facebook in 2014.
The former colleagues sent messages back and forth to check in with one another, and though Edwards couldn't say whether Kelley was telling the truth, she stopped communicating with him after he claimed to buy and shoot animals for fun.
Kelley was accused in 2014 of punching a dog in Colorado. He initially pleaded guilty to animal cruelty but the case was dismissed after he paid fines, CNN reports, citing court documents.
Edwards recalled that Kelley's fascination with mass murders during his time in the service was concerning.
"He would make jokes about wanting to kill somebody," Edwards said. "And we would say, 'wait, that's not funny.' "
She also remembered an instance in which Kelley was being disciplined for poor performance. She warned her supervisors to "back off or he would shoot the place up," based on his frightening behavior in the past.
Kelley was often causing trouble on the Air Force base, Edwards recalled.
He was court-martialed and convicted of assaulting his wife and stepson in 2012, which Edwards said only compounded his problems on the job.
After Kelley threatened officers and tried to sneak guns onto the base, he was referred to a mental health facility for treatment. He attempted to escape the hospital to make good on his previous threats.
The Air Force has been criticized following Kelley's mass shooting as his assault convictions should have barred him from legally purchasing the rifle he used in the First Baptist Church attack. An apparent error occurred within the Air Force and federal law enforcement were not notified of the conviction, so Kelley passed necessary checks to buy the weapon.
On Sunday, Nov. 5, Kelley entered the church in Sutherland Springs and strutted down the aisle of pews, executing his victims.
He killed 26 people in the attack, including an unborn child, and injured at least 20 more. According to Wilson County Sheriff Joe Tackitt, no one escaped the church unscathed.0comments
After the attack, Kelley died of a self-inflicted gunshot wound in his vehicle about 10 miles from the church.
The FBI is currently investigating Kelley's motive and the timeline of the attack, though they are not considering it an act of terror. Instead, evidence shows Kelley may have been aiming to kill his mother-in-law, who sometimes attended the church, after a domestic incident.