David Katz attended a tournament in Jacksonville on Sunday for competitive players of Madden, a football video game. Katz brought a gun into the venue, the GLHF Game Bar, in the back of a pizza restaurant, Jacksonville Sheriff Mike Williams said.
Katz opened fire and killed two people, wounded nine others and turn the gun on himself, the sheriff said.
Here's what we know about Katz so far:
-- Katz is a 24-year-old who hails from Baltimore, Maryland, authorities said.
-- He used a handgun in the shooting, according to a source close to the investigation. Police have not released a motive.
-- Federal agents and local law enforcement officers searched Katz's family home in the Federal Hill area of Baltimore.
-- Katz went by the gaming name "Bread," gamers told CNN, and previously won Madden tournaments in 2017, gamers said.
-- In February 2017, the Buffalo Bills tweeted out a picture of Katz after he won the Madden 17 Bills Championship. "Congrats to David Katz, the Madden 17 Bills Championship winner! Thanks for following along, Bills fans," the tweet read.
-- In an interview with former Buffalo Bills player Steve Tasker, Katz talked about his skill. "I think personally I'm one of the better players," he said.