An Indonesian court jailed a police officer for 18 months on Thursday over negligence contributing to one of the worst stadium disasters in the history of football.

Last year’s crush in the city of Malang killed 135 people — including more than 40 children — after a 3-2 defeat for Arema FC by their fierce East Javan rivals Persebaya Surabaya.

When supporters invaded the pitch of the Kanjuruhan Stadium, police fired tear gas, causing a deadly stampede.

The man jailed on Thursday, Hasdarmawan — who like many Indonesians goes by one name — was a commander for East Java police’s mobile brigade unit.

“(The court is) sentencing the defendant, Hasdarmawan, to one and a half year in prison,” presiding judge Abu Achmad Sidqi Amsya told the court in Surabaya, capital city of East Java.

“The defendant failed to predict a situation that was actually quite easy to anticipate. There was an option not to fire (the tear gas) to respond to the supporters’ violence.”

The sentence was shorter than the three years prosecutors had asked for.

Hasdarmawan had previously denied ordering his subordinates to fire tear gas toward the supporters. Wearing a white shirt and a face mask, Hasdarmawan listened quietly as the judge delivered the sentence.

He has seven days to file an appeal.

Moments later, Bambang Sidik Achmadi, a Malang police officer also accused of ordering his subordinates to shoot tear gas, was found not guilty by the court.

Judge Amsya said the charges had “not been proven”, and the defendant was free to go.

The court was scheduled to pass a verdict on one more Malang police officer for negligence.

Last week, the court sentenced the head of the match organising committee, Abdul Haris, and security official Suko Sutrisno to 18 months and one year in prison respectively.

The former director of the company that runs Indonesia’s premier league has also been named as a suspect and remains under investigation.

October’s tragedy forced Indonesian officials to confront failings in various aspects of the domestic game, which has been blighted for years by shaky infrastructure, mismanagement and violence.

Indonesian President Joko Widodo ordered an investigation and pledged to demolish and rebuild the Kanjuruhan Stadium according to Fifa standards.

A task force investigating the crush has called on the head of Indonesia’s football association and all the members of its executive committee to resign, but they have refused to do so.