JACKSONVILLE, Fla. (AP) - A gunman opened fire Sunday at an online video game tournament that was being livestreamed from a Florida mall, killing two people and then fatally shooting himself in an attack that sent several others to hospitals, authorities said.
 
Jacksonville Sheriff Mike 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 the man died from a self-inflicted gunshot and that authorities were still making final confirmation of his identity with the FBI assisting them in Baltimore.
 
Nine other people were wounded by gunfire and all were in stable condition Sunday evening, Williams said. He added that two others were injured in the chaos as people sought to flee the gunfire.
 
Katz was in Jacksonville for the "Madden NFL 19" video game tournament. The games maker, EA Sports, lists a David Katz as a 2017 championship winner.
 
Thee competition was held in a gaming bar that shares space with a pizzeria. Viewers could watch the games online and see the players.
 
Investigators were looking into 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 a dozen gunshots rings out.
 
Marquis Williams, 28, and his girlfriend, Taylor Poindexter, 26, both from Chicago, were ordering pizza at the bar when they heard the gunfire. Williams said people trampled each other in the panic while trying to get away.
 
"Initially we thought it was a balloon popping, but there weren't any balloons in the room. Then we heard repeat shots and we took off running," said Williams, who participated in the tournament earlier.
 
Jason Lake, the founder and CEO of compLexity, a company that owns professional e-sports teams, said on Twitter that one of his players, 19-year-old Drini Gjoka, was shot in the thumb.
 
Gjoka tweeted: "The tourney just got shot up. Im leavinng and never coming back." Then: "I am literally so lucky. The bullet hit my thumb. Worst day of my life."
 
The sheriff's office used Twitter and Facebook immediately after the shooting to warn people to stay far away and to ask anyone who was hiding to call 911. Police also barricaded a three-block radius around the mall. Officers and Coast Guard boats patrolled the nearby river. Many ambulances could be seen in the area, but the mall area appeared empty of all but law enforcement. Police also took up positions on a bridge overlooking the river.
 
White House spokeswoman Sarah Huckabee Sanders said President Donald Trump had been briefed on the attack and the White House was monitoring the situation.
 
The Jacksonville Landing, in the heart of the city's downtown, also hosts concerts and other entertainment. It was the site of a Trump rally in 2015, early in his campaign for the White House.