Madiun, East Java – Four Indonesian soldiers on Thursday were sentenced to between five and six years in prison for helping to smuggle illegal migrants to Australia.

The Madiun district military court in East Java province found them "legally and convincingly guilty" of people-smuggling last December, when an asylum seeker boat capsized en route to Australia, killing over 200 people.

"They had worked together in an organized manner to carry out people-smuggling," presiding judge Muhammad Afandi said.

Second Sgt. Kornelius Nama, 37, was sentenced to six years in jail for helping to plot pick-up points for the migrants and source boats to pick them up from the shore, he added.

Three other officers were sentenced to five years in jail for their role as lookouts, he added. All four were dismissed from the military and fined Rp 500 million ($52,000) each, Afandi said.

Their sentences followed Monday's conviction of Second Sgt. Ilmun Abdul Said, who was jailed six years over the same incident. Said was the first Indonesian military officer in history to be convicted of people-smuggling, according to the judges. Previous convictions involved civilians.

Last December's incident is believed to be the largest loss of life from a sinking of one of the many boats packed with Asian and Middle Eastern migrants who undertake the often perilous voyage to Australia via Indonesia.

Afandi said the four officers each received between Rp 48 million and Rp 75 million for their role.

Nama furiously protested the verdict, yelling "We are all victims. The police are also involved!" as he was handcuffed and led out of the court.

Australia is facing a steady influx of asylum seekers arriving by boat, many of whom use Indonesia as a transit hub and pay people-smugglers for passage on leaky wooden vessels after fleeing their home countries. Hundreds of boatpeople have died en route to Australia this year.