Clustered outside an Indonesian courthouse, students clapped when they heard a judge convict two policemen in the killings of campus protesters. Seconds later, they groaned in disappointment when the sentences were announced.

The Indonesian military judge sentenced the officers to four years and 10 months in prison for failing to control troops accused of gunning down four students at a pro-democracy rally in May. The crowd called the punishment too soft.In a flurry of internal trials and probes, Indonesia's military - the most stable institution in a fragile land - has embarked on a campaign to atone for abuses under its authoritarian boss, former President Suharto.

Critics, however, say the investigations are cosmetic, focusing largely on lower-ranking scapegoats in a bid to appease demands for reform.

The military is counseling patience, saying those who allegedly shot the student protesters earlier this year are under arrest and will be punished harshly if convicted.

The 490,000-member military, which includes the police, is harried by more than just a negative image as Indonesia buckles under economic hardship. Budget cuts are diminishing the ability of the armed forces to keep order in this archipelago nation of 200 million people.

Yet the military is still widely viewed as the only force that can preserve unity in a country ravaged by inflation and joblessness.

In May, as many as 1,200 people were killed in riots in the capital. Some of Jakarta's anti-riot units were hundreds of miles away in the city of Medan, where street violence had broken out earlier.

The unrest loosened Suharto's grasp on power, and his successor, B.J. Habibie, has ushered in an enthusiastic, if at times unruly, experiment with democracy.

In Indonesia's new era of reform, the military is under scrutiny as never before.

Anxious to shed a legacy of suppressing dissent, armed forces chief Gen. Wiranto has launched two high-profile investigations:

- With two already convicted, another 16 police officers face trial in the shooting deaths of the student protesters at Jakarta's Trisakti University.

- Ten members of Indonesia's special forces have been arrested for alleged involvement in the kidnapping and torture of more than two dozen activists. Also under investigation is Lt. Gen. Prabowo Subianto, son-in-law of Suharto and former head of the elite unit.

But government opponents fear other commanders possibly linked to the kidnappings will not be targeted. And 14 activists remain missing and are feared dead.

"Prabowo, of course, did not do it by himself. There was some net-working by the army," said Amien Rais, a prominent opposition figure who believes civilian prosecutors should investigate the military's entire command structure.

"This is only a political joke," he said.

The panel of military officers investigating the abductions, known as the "honor council," has barred the public from hearings.

A host of other accusations taint the military, including alleged arbitrary killings and torture in several provinces that harbor small bands of separatist rebels.

In Aceh province, Wiranto publicly apologized for military abuses and said he would pull out some troops, as he has done in the former Portuguese colony of East Timor.