Sixteen months ago, David Katz was attracting public attention for his video game prowess with a spectacular last-gasp victory during EA Sports’ Madden gaming tournament.

The Baltimore native was behind “the most exciting moment” of the 2017 series, according to the game’s publisher, pulling off an “unbelievable pass as time expired to be crowned Buffalo Bills Champion” in the New York tournament in April of that year.

The NFL team later posted an image to its Twitter account congratulating the gamer, while an announcer admitted there was “a lot of pressure on these young men” during the live-streamed events. “You have to give it up to Bread,” he added, using Mr Katz’s nickname.

The Madden series of games allows players to create a team of NFL players to take on the league. In competitions, both online and in person, gamers compete for cash prizes.

Commentators described Mr Katz as “a man of business”, and “very, very focused”.

Little more than a year later, the 24-year-old is accused of shooting dead two fellow gamers and wounding nine other people before turning the gun on himself at a tournament in Jacksonville, Florida.

Sheriff Mike Williams said final confirmation of the suspect’s identity was still pending.

At 1.34pm on Sunday, police started receiving panicked calls saying people had been shot at the Chicago Pizza restaurant in the Jacksons Landing complex. Officers arrived two minutes later, Mr Williams said.

Mr Katz’s body was found near those of the two victims, the sheriff added, saying he had taken his own life.

Mr Williams declined to discuss a potential motive for the attack, and investigators are keeping an open mind.

Unconfirmed reports suggested, however, that Mr Katz had been unsuccessful during the tournament. Witnesses said he had been eliminated, while others claimed he was disqualified, although why this may have happened is still unclear.

Police have not identified the victims, but family members told local TV station WJAX that the two people killed were Eli Clayton and Taylor Robertson, both fellow contestants.

The Miami Herald also identified the victims, saying Mr Robertson, 27, was from Ballard, West Virginia while Mr Clayton, 22, lived in Woodland Hills, California.

Mass shootings in America Show all 8 1 /8 Mass shootings in America Mass shootings in America Camden shootings – 1949 Howard Unruh killed 13 people, including three children, during a 12-minute walk through his neighborhood on September 6, 1949, in Camden, New Jersey, when he was 28 years old. The incident became known as the "Walk of Death". Unruh was found to be criminally insane and died in 2009 after a lengthy illness at the age of 88, following 60 years of confinement. Alamy Mass shootings in America University of Texas tower shooting – 1966 Charles Whitman killed 17 people and injured 31 others in Austin, Texas. After stabbing his mother and wife the night before, he headed to the University of Texas, where he opened fire on people in the campus and streets from the observation desk. He was shot dead after a policeman and civilian reached the scene. Austin History Center, Austin Public Library Mass shootings in America Easter Sunday Massacre – 1975 James Ruppert killd 11 family members in his mother's house, which included his mother, brother and his wife, as well as their eight children. He used a magnum, two handguns and a rifle. Mass shootings in America Wilkes-Barre shootings – 1982 Former prison guard, George Banks, shot dead 13 people in Pennsylvania, including five of his own children. AP Photo/Times Leader Mass shootings in America Wah Mee massacre – 1983 Three men, Kwan Fai Mak, Wai-Chiu Ng, and Benjamin Ng, killed 13 people who were in Seattle's Wah Mee gambling club. YouTube/KIRO 7 News Mass shootings in America San Ysidro McDonald's massacre – 1984 James Huberty killed 21 people and injured 19 others after he walked in a McDonald's in San Diego. He was shot dead by a sniper after 78 minutes of him entering the restaurant. Alamy Mass shootings in America Palm Sunday massacre – 1984 Ten people were shot dead from handguns at close range in a New York home. A baby girl was the only survivor after convicted dealer, Christopher Thomas, shot three women, one teenage girl and six children in their Brooklyn home. Thomas was convicted of manslaughter and cleared of murder. He was released from prison after 32 years. Mass shootings in America Edmond post office shooting – 1986 Patrick Sherrill, a postal worker at the Edmond post office in Oklahoma, killed 14 co-workers and injured 6 others, before he shot himself. Oklahoma Highway Patrol Collection

FBI officers and police have raided Mr Katz’s family home, in the Inner Harbour area of Baltimore.

Bureau spokesman Dave Fitz confirmed agents had gone to Mr Katz’s father’s house. He declined to release specific details, saying the investigation was ongoing.

T J Smith, chief spokesman for the Baltimore Police Department, said the force was assisting other agencies “with some information that has led authorities to Baltimore”.