Deadly violence stunned gamers competing Sunday in Jacksonville during a Madden NFL 19 video game tournament. Jacksonville Sheriff Mike Williams said the gunman killed two people and shot nine others before fatally shooting himself.

A former Calabasas football player is among the deceased in the Jacksonville shooting on Sunday, according to a Twitter account for the Calabasas High School Coyote Football team.

“Our hearts are broken as we learned that former Calabasas Football player @True__818 (Elijah Clayton) was senselessly murdered today during the mass shooting in Florida. We send our love, condolences, and deepest sense of sorrow to Elijah’s Family and Friends,” the football team expressed on social media.

The competition was held in a gaming bar that shares space with a pizzeria. Viewers could watch the games online and view the players.

Williams said authorities believe 24-year-old David Katz of Baltimore carried out the attack using at least one handgun at the Jacksonville Landing, a collection of restaurants and shops along the St. Johns River.

He said final confirmation of the suspect’s identity was pending as the FBI in Baltimore aided in the investigation.

The sheriff said Katz was attending the tournament in Florida. The “Madden” game’s maker, EA Sports, lists a David Katz as a 2017 championship winner.

“No one deserves to die over playing a video game, you know?” said “Madden” competitor Derek Jones, 30, of Santa Fe, New Mexico. “We’re just out here trying to win some money for our families and stuff.”

Nine other people wounded by the gunfire were all in stable condition Sunday evening after being taken to hospitals, Williams said. He added that two others were injured in the rush to flee the gunfire.

Investigators were looking into an online video that appeared to capture the scene right before the shooting began, Williams said. A red dot that appears to be a laser pointer is visible on the chest of a player seconds before the first of about a dozen gunshots rang out.