The suspected gunman in Sunday’s fatal mass shooting at a Jacksonville gaming tournament was recently seen in an interview bragging about his video game skills.

David Katz allegedly killed two people and injured several more before turning the gun on himself in a chilling scene that was broadcast on the online gaming platform Twitch.

A fellow competitor at the Madden tournament told the Los Angeles Times that Katz, 24, had been participating in the tournament on Sunday and lost the match before he opened fire on the crowd of players. When police responded to emergency calls about an active shooter, they found two victims dead along with Katz.

A year prior, Kats had reportedly performed unexpectedly well at another Madden tournament in Burbank, California, and gave an interview after winning the tournament, though he had arrived to the tournament as the seventh-seeded player. The video of his interview was first obtained by the New York Post:

“I don’t think of myself as a seventh seed,” Katz said in the post-game interview.

“I think personally, I’m one of the better players — and I like to let my game prove that,” he said.

“He’s a well-known competitor,” another competitor at the Florida tournament told WJAX-TV.

“[He was here] all weekend,” the man said. “He had shades on, he didn’t speak to anybody. Even after we played…I went to shake his hand and just tell him good game and he just looked at me. He didn’t say anything.”

Authorities have not yet determined a clear motive for the shooting or how long in advance Katz may have planned the massacre.