An Indonesian court jailed a football club's organizer and its chief of security on Thursday for negligence resulting in the tragic deaths of 135 people due to the police's use of tear gas during a match at the stadium last October, leading to a frenzied stampede for the exits.

The disaster in Kanjuruhan stadium in East Java's Malang city was among the world's worst sporting tragedies.

The panel of three judges at Surabaya District Court, which was under heavy police guard, convicted Abdul Haris, the Arema FC Organizing Committee chair, and the club's security chief, Suko Sutrisno, of criminal negligence causing death and bodily harm following a nearly two-month trial. About 140 witnesses testified during the trial.

Haris was sentenced to 18 months in prison and Sutrisno to 12 months, far below the more than six years sought by prosecutors for each of them.

Presiding Judge Abu Achmad Sidqi Amsya said the defendants had not verified the safety of the stadium since 2020 and "did not prepare an emergency plan."

The crowd's panic after the tear gas was fired caused a crush at six exits, where many fans were killed, he said.

"The defendants' mistake has caused intense grief for the victims' families, as well as triggering a negative stigma for Indonesian football in the eyes of international society," Amsya said.

The judges said they considered several factors in reducing the sentences, including Haris's long involvement in advancing Indonesian football. Both the defendants and prosecutors said they are considering whether to appeal the sentences. An appeal must be filed within seven days.

It was among the deadliest football-related tragedies since a 1964 crush in Peru killed over 300 people.

Police fired the tear gas when fans flooded the pitch after Arema FC was defeated in a home match for the first time in 23 years by rival Persebaya Surabaya.

The match was attended only by Arema fans, as organizers had banned Persebaya supporters because of Indonesia's history of violent football rivalries.

Three police officials who allowed or ordered the officers to use tear gas are being tried at the same court on the same charges. Prosecutors have demanded three-year prison terms and the court is expected to hand down its verdict within weeks.

At least 11 officers fired tear gas – eight canisters into the stands and three onto the pitch – to prevent more spectators from taking to the field after the game.

Police described the pitch invasion as a riot and said two officers were killed, but survivors accused them of overreacting. Videos showed officers kicking and hitting fans with batons and forcibly pushing spectators back into the stands.

National Police Chief Listyo Sigit Prabowo removed the police chiefs of East Java province and Malang district and suspended 20 other officers over violations of professional ethics after the tragedy.

An investigation set up by Indonesian President Joko Widodo in response to a national outcry over the deaths concluded that the tear gas was the main cause of the crowd surge. It said police on duty had no knowledge that the use of tear gas is prohibited at football stadiums and used it "indiscriminately" on the field, in the stands and outside the stadium, causing the more than 42,000 spectators inside the 36,000-seat stadium to rush to the exits - several of which were locked.

Widodo's fact-finding team also concluded that the national football association PSSI had been negligent and ignored safety and security regulations. Its chair and executive committee were replaced last month and it is now led by Erick Thohir, the former owner and chairman of Italian football giant Inter Milan and U.S. football club D.C. United, who has served as Indonesia's minister of State-Owned Enterprises since 2019.

Authorities in Surabaya, the capital of East Java province, deployed 360 police to secure the court for its ruling Thursday.

Arema fans, known widely as "Aremania," were prohibited from coming to Surabaya during the trial to avoid any clash with Persebaya fans.

Devi Athok, a resident of Malang who had two daughters who were killed in the crush, said he was disappointed by the ruling in a trial with such a large number of victims.

"I don't understand and am very disappointed to hear the verdict," Athok said in an interview with Kompas TV. "It doesn't provide justice for the victims and doesn't follow the facts and evidence."

He said he hopes that prosecutors will appeal the sentences "so that justice is truly upheld."