A military court in Jakarta has begun hearing the case against four Indonesian soldiers accused of carrying out an acid attack on an activist who opposed the growing role of the armed forces in civilian government.

On Wednesday, military prosecutors formally charged the four men — Edi Sudarko, Budi Hariyanto Widhi Cahyono, Nandala Dwi Prasetia and Sami Lakka — with premeditated aggravated assault. Under Indonesia’s criminal code, the offence carries a maximum penalty of 12 years in prison.

The defendants, dressed in military uniforms and accompanied by lawyers appointed by the armed forces, attended the opening session. Their defence counsel told the judges that the accused would not challenge the indictment, allowing proceedings to move forward without objection.

The assault took place on March 12, when Andrie Yunus, a deputy coordinator at the Commission for Missing Persons and Victims of Violence (KontraS), was riding his motorcycle in Jakarta. Two men on another motorcycle approached him and threw acid in his direction.

According to military prosecutor Mohammad Iswadi, the 27-year-old activist suffered burns to more than one-fifth of his face and body and lost vision in one eye as a result of the attack.

Initial police investigations, based on closed-circuit television footage, pointed to two different suspects. However, authorities later arrested four men in connection with the case.

All four suspects were members of the Indonesian military’s Strategic Intelligence Agency. The agency’s chief resigned after the arrests, though no official explanation for the resignation was given.

Prosecutor Iswadi told the court that the accused acted out of anger toward Andrie’s activism but were not carrying out orders from superiors.

On the day of the attack, Andrie had just completed recording a podcast in which he criticised what he described as the increasing militarisation of Indonesia’s government under President Prabowo Subianto, a former army general.

He had also publicly opposed a legislative amendment passed last year that allows active-duty military officers to hold a broader range of civilian government positions, including posts within the attorney general’s office, the national disaster mitigation agency and the counterterrorism body.

Human rights organisations argued that the change would expand military influence in public administration and raise the risk of abuses of authority and violations of civil liberties.

“The suspects believed Andrie Yunus had insulted and disrespected the military as an institution,” Iswadi told the court.

Separately, Indonesia’s National Commission on Human Rights (Komnas HAM) has stated that as many as 14 individuals may have been connected to the incident.

The commission warned that such an attack could create a chilling effect, discouraging members of the public from voicing criticism of government officials.

According to the prosecution, the four accused planned the assault while staying at military housing in Jakarta.

One of the men allegedly obtained a rust-removal chemical from a military workshop and combined it with battery fluid before the group set out on motorcycles to locate Andrie.

The court is scheduled to reconvene on May 6, when prosecutors are expected to present witness testimony.