A gamer opened fire at the bar after he lost a match in Jacksonville, Florida on Sunday, making it the 237th shooting in the USA this year to date.
According to the father's version of events, the relationship between mother and son got increasingly worse.
"True is consistently one of the best in competitive Madden", the biography on his profile page said.
Seven members of the Jacksonville Fire Station 1 - known as "The Rock" - were doing routine training in a parking garage across the street from the Landing, when dozens of people came running out, said Randy Wyse, president of the Jacksonville Association of Fire Fighters. "I was anxious about the guys @BeastModeMac816 @JoelCP_ and myself at that moment". Our teams have been working non-stop to do what we can to respond to this awful situation.
Two of those competing Sunday were killed, police said: Elijah Clayton, 22, of Woodland Hills, Calif., and Taylor Robertson, 28, of Giles, W.Va.
Alexander Madunic, a gamer who was shot in the foot, said the shooter lost a game in the Madden tournament earlier in the day and was angry.
"The event was a qualifying tournament for the Madden Classic, our first Madden EA Major competition of this season".
In the immediate aftermath of the shooting, there were immediate calls for heightened levels of security for future events.
We've all been deeply affected by what took place in Jacksonville. "That's when I was like, man, I just made the decision to jump on top of the guys".
The local community shocked by the events as well after Katz's ties to the DMV were announced. He told Fox 45 Now he's glad Katz only used a handgun during the shooting.More news: YouTube gamer kills himself, a mother and daughter in high-speed crash
Former Congresswoman Gabrielle Giffords, who was seriously wounded in a mass shooting, said the nation's attention turns to Florida, again. Katz attended Hammond High School in Columbia, Maryland, and went on to the University of Maryland beginning in 2014.
Richard Katz, a NASA engineer, said his ex-wife had "an obsession with using mental health professionals and in particular psychiatric drugs to perform the work that parents should naturally do". Maryland state law also prohibits the sale or transfer of a gun to someone who has been diagnosed with a mental disorder or who has a history of violent behavior.
Police say that Katz's guns were purchased within the last few weeks. 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 rings out.
Clayton's cousin, Brandi Pettijohn, spoke on the family's behalf, saying family was "devastated by yet another senseless act of gun violence".
"My cousin has to bury her firstborn".
Nine others were injured during the shooting before Katz killed himself, officials stated.
Timothy Anselimo, or "olarry", was shot three times, according to his mother's Twitter page.
"He upset. He's depressed".
"When it hits this close to home, it's going to be especially hard", Foss said. The dispatcher encouraged her not to say anything further until a police officer arrived. The location, in the heart of the city's downtown, also hosts concerts and other entertainment.
Kivlen tells The Associated Press that 24-year-old David Katz didn't talk much with fellow gamers, either online or when they met face-to-face for Madden tournaments.
"Why are young men willing to give up their life, or why don't they value somebody else's life?" he said.