Devin Kelley, the Texas church shooter, apparently had a trigger-happy temper, according to Ralph Martinez, who was his best friend during their teenage years.

"He was like a brother to me at the time," Martinez told the Daily Mail.

Martinez expressed shock at the news of his best friend opening fire on a community church gathering in Sutherland Springs, Texas, in which 26 people died and 24 others were left injured.

"When I heard the news of what Devin did I was mortified. I never thought he could be capable of such an evil. I’m hoping this is all a bad dream."

Martinez also revealed that during their growing up years, he saw Kelley getting engaged in several verbally aggressive arguments, however, he never saw Kelley get physical with anyone. "He was all talk, no action. I never imagined this could happened."

Martinez, who is a car dealer, told the Mail he met Kelley at a skate board park in New Braunfels, Texas, when he was 12 and Kelley was 11. After their first meeting, they got along well as friends.

"Devin had authority issues growing up says Martinez. Nothing really over the top, he just didn’t like to be told what to do, especially by his parents, he would constantly get into arguments with them."

Martinez added: "When they asked him to do a simple task like cleaning up his room, he would immediately do it, he would ask them why? But he eventually did what they asked him to do."

However, Kelley's former girlfriends disclosed that his behavior included harassment and other weird incidents.

"Years after dating me he would try to bribe me to hang out with him," Katy Landry, one of Kelley’s former girlfriends, told NBC News. "He ended up assaulting me. He would stalk me by repeatedly calling me – even prank calling me, saying really weird stuff," she added.

"That was another thing about him — he was very sick in the head...He would tell me very sick strange things," she said, without revealing further details.

Another former girlfriend, Brittany Adcock, 22, who dated Kelley for two months when she was 13 and he was 18, said: "At the time I didn't think much into it being so young but now I realize that there's something off about someone who is 18 with someone who is 13," she said.

Adcock said he kept harassing her even after they broke up.

One of Kelley's school mate at New Braunfels High School, Patrick Boyce, told the Daily Mail: "He had a kid or two, fairly normal, but kinda quiet and lately seemed depressed."

"He was the first atheist I met. He went Air Force after high school, got discharged but I don't know why." "I was just shocked [to hear the news]. Still haven’t quite processed how he could have done that." Boyce added.