A competitor in a Madden NFL 19 tournament in Jacksonville, Florida, opened fire during the event on Sunday afternoon, killing two people before taking his own life, according to police.

At a news conference Sunday evening, Sheriff Mike Williams of the Jacksonville Sheriff’s Office identified the shooting suspect as David Katz, 24, of Baltimore. Williams said that Katz was at the Madden tournament as a competitor, and that Katz shot and killed multiple people and then fatally shot himself.

Following a second news conference Monday afternoon, the sheriff’s office said that authorities had identified the two deceased victims as other competitors in the Madden tournament: 22-year-old Elijah Clayton of Woodland Hills, California, known in the esports community as “TruBoy,” and Taylor “SpotMePlzz” Robertson, 28, of Giles, West Virginia.

The tournament was being livestreamed on Twitch at the time of the shooting. Twitch took down the clip in question, but archives are available on Twitter and YouTube. You can see one of them below.

In the video, competitor Wesley “Joe Rice” Gittens is playing Clayton. A red dot, apparently a laser targeting sight, can be seen on Clayton briefly before the screen drops the competitors’ images and the shooting begins. As nine shots ring out, competitors can be heard abandoning their stations, and others are heard fleeing. Then a man is heard crying out, “What did he shoot me with?” Three more shots are fired and screaming can be heard.

[Warning: The following video contains disturbing content.]

Twitch livestream of Madden NFL tournament qualifier in Jacksonville broadcasts mass shooting, horrific aftermath [video disturbing]https://t.co/kKcpNuGFRi pic.twitter.com/98FwkWMfOp — Timothy Burke (@bubbaprog) August 26, 2018

This weekend’s event at Jacksonville Landing downtown was the first of four qualifier tournaments for the Madden Classic series sponsored by EA Sports. The tournament was being held at GLHF Game Bar at Jacksonville Landing, while the shooting took place next door at Chicago Pizza.

Katz was carrying two handguns and extra ammunition at the time of the shooting, Sheriff Williams said Monday, though he added that Katz appears to have fired only one of the weapons. Sheriff Williams said Katz purchased both handguns legally from a licensed dealer in Maryland.

According to the sheriff’s account of the shooting, Katz “clearly targeted other gamers,” walking past patrons at the pizza restaurant to reach the group of Madden players in a back room. Although reports have suggested that Katz opened fire after being eliminated from the tournament, Sheriff Williams said that authorities have not determined a motive yet, and that Jacksonville police are continuing to investigate the crime with assistance from the FBI.

Officials said Monday that in addition to the two slain men, 10 people were wounded by gunfire and one sustained a “non-gunshot-related” injury. All surviving shooting victims expected to recover from their injuries, according to the sheriff.

In a statement posted to Twitter on Sunday night, Electronic Arts described the incident as “a senseless act of violence that we strongly condemn.” The company added that its current focus is “on those affected, and supporting law enforcement as they continue their investigation into this crime.”

EA released another statement Monday afternoon on Twitter, after the police announced who had been killed in the shooting. Describing the incident as “an inconceivable tragedy,” the company said Robertson and Clayton “earned the admiration of all who watched them compete” and added that “we will miss them greatly.”

EA CEO Andrew Wilson issued a statement Monday night confirming that three previously scheduled Madden qualifying events were cancelled in wake of the shooting.

“While these qualifying events are operated independently by partners, we work with them to ensure competitive integrity and to gather feedback from players,” Wilson wrote. “We have made a decision to cancel our three remaining Madden Classic qualifier events while we run a comprehensive review of safety protocols for competitors and spectators. We will work with our partners and our internal teams to establish a consistent level of security at all of our competitive gaming events.”

Katz, also known as “Bread,” “Sliced Bread” and/or “ravenschamp,” was the club champion representing the Buffalo Bills in the Madden NFL 17 competitive year. On Monday, the Associated Press reported that Katz had been hospitalized twice during his teen years for mental illness. The information came from court records of Katz’s parents’ 2007 divorce.

Drini Gjoka, a top-flight Madden esports competitor for compLexity Gaming, described a horrifying scene and said he was hit in the hand by a stray round.

The tourney just got shot up. Im leavinng and never coming back — Drini Gjoka (@YoungDrini) August 26, 2018

I am literally so lucky. The bullet hit my thumb — Drini Gjoka (@YoungDrini) August 26, 2018

Chris “Dubby” McFarland said he had been grazed in the head by a bullet but was also OK.

They took me to the hospital. Bullet grazed my head. I feel fine, just a scratch on my head. Traumatized and devastated. — DUBBY (@DubDotDUBBY) August 26, 2018

All the time you hear about these shootings and pray for everyone involved. Donate money. Raise awareness and do everything you can. But to be in the room getting shot at and seeing your friends dead......man — DUBBY (@DubDotDUBBY) August 26, 2018

Others at the event told friends via social media that they were present for the shooting but safe.

Please everyone keep your thoughts and prayers for my brothers. — Kiv (@young_kiv) August 26, 2018

CompLexity gave this statement confirming Gjoka was injured in the shooting:

We’re obviously shocked and saddened by this afternoon’s events. Our player, Drini, was hit in the thumb but is going to be fine. He managed to escape and run down the street to a nearby gym. He’s currently cooperating with the authorities and we will be flying him out of Jacksonville as soon as we are given the green light from the officials on the ground.

The Los Angeles Times reported Sunday afternoon that the suspect was a competitor at the tournament who had lost. Veteran esports reporter Rod Breslau reported the same information, and said oLARRY2K, of Bucks Gaming in the NBA 2K League, was also wounded.

According to @ImSteveyJ, the Jacksonville shooter was a competitor in the Madden tournament that lost, opened fire on multiple people after, and then killed himself. One person hit includes NBA 2K pro player @oLARRY2K. https://t.co/0eHARZV049 — Rod Breslau (@Slasher) August 26, 2018

oLARRY’s mother confirmed that her son was hit three times.

My son was shot 3 times please keep him in your prayers — Sujeil (@olarrysmom) August 26, 2018

Update: This story has been substantially revised since its first version and subsequent updates. Polygon will continue to revise and update this story as more developments become known.