Eli Clayton, 22, of California, and Taylor Robertson, 27, of West Virginia, were identified by Electronic arts, the company which develops "Madden", as the victims who were fatally shot on Sunday.
"We believe the suspect to be 24-year-old David Katz of Baltimore, Maryland".
A video game tournament turned deadly in Florida after a gunman opened fire, killing 2 people and injuring several others.
Jacksonville sheriff Mike Williams confirmed on Monday that 10 victims have been treated for gunshot wounds, while one was treated for an injury incurred while fleeing the scene. A rival of the shooter recalled that the 24-year-old didn't talk much with fellow gamers, either online or when they met face-to-face for tournaments. Seven had been shot, Williams said.
Katz is known to have gone by the gamer monikers "RavensChamp", "Bread" and "TREXHAVAHARTATAK".
Three people, including the gunman, were killed in the shooting, and 11 more were injured.
The FBI and Baltimore Police on August 26 the home of Katz and interviewed family members, the agencies wrote on social media.
President Trump has not yet reacted to the incident, but his daughter Ivanka tweeted: "As we await further details, our hearts are with Jacksonville and all those affected by today's tragic mass shooting". "He loved his family more than anything".
During the event, the Jacksonville Sheriff's Office took to Twitter to warn people to stay away from the Jacksonville Landing - urging people: "please don't come running out". Clayton was also a frequent face at EA Majors.
Tony Montagnino, who goes by "G-Tech", said that he got struck twice in the lower body: "One went through". I'm leaving and never coming back. "Life can be cut short in a second", he said.
Katz had past success at video game tournaments, winning the Madden Bills Championship in 2017, along with $3,500 and the chance to compete in a later contest in Los Angeles.
In another circulated video, an announcer describes Katz, who's seen in the captured livestream, as someone who "keeps to himself".