READ: Who were the victims killed in the Jacksonville mass shooting?
Dennis Alston, known as “Evil Ken" in the Madden world, came to Jacksonville from New Jersey to play in the Madden Tournament.
He said he never expected it to end how it did.
“I seen some good people dead, man," he said. "I seen people on the floor dead."
Alston says he tried to shake suspected shooter David Katz's hand after beating him in a round in the tournament, but Katz stared at him blankly.
He says Katz was acting weird and wearing the same clothes as the day before.
Police say Katz later left the game room at Chicago Pizza and came back with a gun.
Alston said he witnessed Katz fire as many as 10 shots. He says he couldn’t tell the type of weapon but said it appeared to have a laser.
"[He] pointed my way, I had to cover," he said.
Jacksonville Sheriff Mike Williams said officers found three people dead at the scene, including the gunman.
Gamers Eli Clayton and Taylor Robertson were identified as the two people killed.
Nine people were rushed to the hospital with gunshot wounds. Two other victims had injuries, but took themselves to the hospital.
Alston is a more than 10-year veteran of the EA Sports Franchise. On Sunday, he says he witnessed some of his closest friends gunned down in front of him.
He says he doesn't believe Katz targeted people who beat him because he and another gamer beat the alleged shooter, and both are still alive.
“You can’t put it into words. It’s stuff you see in movies, man," he said. "No words for it. There’s no place for it in this world for it.”
Eli "trueboy" Clayton, a former high school football player, was identified by the Calabasas High School football team in California.
Clayton, 22, was in Jacksonville from Los Angeles for the tournament.
In March 2017, Jaxson Deville presented him a check after he took the Jaguars to the national finals in the Madden 17 quarterfinals held in Jacksonville.
In his Instagram bio, he identified himself as a Madden Pro player. He gamed under the name Trueboy. In a social media post, Clayton posted about how excited he was to appear on ESPN and how it was a dream since he was 5 years old.
In February, Clayton wrote:
"Madden has really changed my life and a game that I used to play for fun is now a big part of my life. Just so blessed to have an opportunity like this. Just such a crazy feeling knowing that tons of people log on and see my face on a Madden NFL game. Unreal."
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Based on several posts, Clayton appeared to be a Jacksonville Jaguars fan. In a post, he took a screenshot of himself in a Madden game as a Jaguars coach.
Robertson was a 27-year-old of Ballard, West Virginia. A Facebook profile under the same name shows pictures of him posted in 2013, from a wedding, as well as a young boy in a cover photo.
He identified himself as a father, husband and pro Madden player on his Twitter account @spotmeplzzz, and often tweeted about his family and son. He was a Tennessee Titans fan.
In a Aug, 20 tweet, he wrote: "Excited for some live madden this weekend in Jacksonville. Time to chase that second belt."
Robertson died Aug. 26 -- exactly 3 months shy of what would have been his 28th birthday on Nov. 26.
He and Clayton were Facebook friends.