YOGYAKARTA, Indonesia — A group of 12 soldiers from Indonesia's elite special forces went before a military court Thursday for allegedly storming a prison on the main Java island and killing four detainees to avenge the murder of a fellow soldier.

Prosecutors say the well-trained soldiers wore masks when the broke into Yogyakarta's Cebongan prison on March 23 looking for four men who were being held on charges of killing a member of the elite army unit, known as Kopassus. They tortured several guards and forced them to open the jail cell and shot the four with automatic weapons before destroying surveillance cameras, sparking a national outcry.

In a rare acknowledgment of military abuses, the Indonesian government issued a statement soon after, promising justice would be served.

The 12 were put on four separate trials at a military court in Yogyakarta, an Indonesian province. Prosecutors charged them with premeditated murder which can carry a death penalty.

"They admitted have took part in the attack," said military prosecutor Lt. Col. Sugiharto, "It was motivated by a strong feeling of unity and dignity of the corps after learning their fellow soldier Chief Sgt. Heru Santoso was brutally murdered by the four thugs."

The high-profile case seen is a test on how far the military has come since Washington resumed some assistance to Kopassus three years ago. The outfit earlier faced questions over its human rights record.

Human rights activists have warned that the trials of the 12 are likely to be little more than a sham, while the U.S. late last month promised to watch how Indonesia handles the case.

"These courts should never be used to try those accused of human rights violations. They are biased, and they create an intimidating environment for witnesses to testify," Isabelle Arradon, Amnesty International's deputy Asia-Pacific director, said in a statement.

Kopassus troops have been implicated in a range of crimes and human rights violations over the years and officials say they have worked to address the problem.