(CNN) One of the men shot and killed at a gaming tournament in Jacksonville, Florida, on Sunday had won the national tournament, the Madden Classic, two years ago.

The other was a former high school football player who loved to play the online version of his favorite sport, and had won $51,000 in his short gaming career.

They both died in the shooting at the GLHF Game Bar on Sunday, where they were attending a tournament for competitive players of the football video game, Madden. The winners would go on to a higher level tournament in Las Vegas in October, where large cash prizes could be won.

The shooting left 10 injured from gunshots and one person with a non-gunshot injury, Sheriff Mike Williams said. All of the injured are expected to survive, he said. Three of the four people hospitalized at Memorial Hospital have been released, officials said.

The sheriff's office on Monday identified the two victims who died as Elijah Clayton and Taylor Robertson.

Taylor "spotmeplzzz" Robertson

Taylor Robertson

"We are shocked and deeply saddened by the senseless violence in Jacksonville and the tragic deaths of Dot City Gaming team member, Taylor "SpotMePlzzz" Robertson, and Eli "True" Clayton," Robertson's gaming sponsor said in a two-part tweet

"They were great competitors and well-loved members of the Madden community. Our thoughts and deepest sympathies go out to their families, loved ones, and all of those affected by this tragedy."

The 27-year-old Robertson, who was from West Virginia, had career winnings of more than $80,000 and had won the Madden NFL 17 Classic, according to his player profile on EA Sports . Sunday's tournament was a qualifying round for the Madden NFL 19 Classic.

Robertson was a 2009 graduate of James Monroe High School, according to CNN affiliate WVNS-TV . A vigil was held at the school Monday, where Robertson's friend Andrew Evans told WVNS he was a couple of years younger than the star athlete so he looked up to him as a hero.

"He's invincible," Evans said. "Things like this don't happen to people like that."

He also told CNN affiliate WVVA-TV that Robertson was a first team all-state football and basketball player.

"He was the most humble human being to have the abilities and the talents that he did," Evans said.

Robertson was known to Monroe students as "The Taylor Robertson," Evans said.

Eli "trueboy" Clayton

Eli Clayton

Clayton was a former member of the Calabasas High School football team in California, the team said.

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 pic.twitter.com/xhdQ8TLg0d — CHS Coyote Football (@CalabasasFtball) August 27, 2018

"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 team tweeted.

Calabasas High School Principal CJ Foss told CNN affiliate KABC-TV her staff has been deeply affected by the shooting in Jacksonville.

"He was amazingly kind-hearted," Foss said. "He was a contributing member of our campus."

Clayton, 22, was from Woodland Hills, California. He also went by "true," according to his EA Sports player profile. He attended Calabsas High during the 2013-2014 school year, KABC reports.

"When it hits this close to home, it's going to be especially difficult," Foss said.

"True is consistently one of the best in competitive Madden," the biography on his profile page said.

Clayton's cousin Brandi Pettijohn said in a statement that the family was "devastated by yet another senseless act of gun violence."

"Elijah's family wants you to know that he was a good man. He did not believe in violence. He never even had a fistfight. He loved football and out of all the video games he could play -- he settled and mastered Madden. He made a good living gaming and he saved his earnings so he can afford to go to college to continue his education."

Gunman David Katz, a 24-year-old gamer from Baltimore, was in Jacksonville for the tournament. He used at least one handgun in the shooting, Williams said. Police have not released a possible motive.

'Worst day of my life'

Several of those who were injured posted their stories on Twitter.

Tony Montagnino, who goes by "G-Tech," said he was struck twice in the lower body: "One went through. The other was lodged," Montagnino tweeted. "Still doesn't feel real. Saw a lot of things today I wish I hadn't seen. But I also saw a community of people rally around each other and a massive amount of support from friends and family to check on everyone. I'm thankful for everyone of you guys in the community. I love y'all."

Drini Gjoka, also known as "YoungDrini," called Sunday the "worst day of my life" on his verified Twitter page . Gjoka was struck in the thumb.

In another tweet, he said: "I will never take anything for granted ever again. Life can be cut short in a second."

My sons Bucks gaming book bag with his blood from being shot pic.twitter.com/1oJSocbf3h — Sujeil (@olarrysmom) August 27, 2018

Sujeil Lopez told reporters her son, Timothy Anselimo, or "olarry," was shot three times, once in his chest, once in his hip area, and once in his right hand.

Lopez posted several photos of her son in the hospital with Gov. Rick Scott and a photo of her son's bloodied backpack.

"He didn't deserve this, and now that he's facing the fact he might not even be able to use his hand ever again -- is extreme," she said.

Her son has been playing video games since he was little, Lopez said.

"As a mother, you want your child to be great. As a mother, you want your child to succeed and do what they love," she said.