Two crew members of Indonesia's national flag carrier Garuda are being questioned in connection with the murder of a prominent human rights activist who died on board a flight to Amsterdam last year, police said on Tuesday.

An autopsy by Dutch police on Munir, a vocal critic of former Indonesian leader Suharto, found he was poisoned with arsenic.

Indonesian police said investigators had been grilling Garuda steward Oedi Irianto and stewardess Yeti Susmiarti since Tuesday morning over the case.

"Both were summoned in the capacity as suspects and they are now undergoing investigation. Their roles cannot be revealed yet as investigators are still working on it," said national police spokesman Inspector General Aryanto Boedihardjo.

A Garuda spokesman could not be immediately reached for comment, but a lawyer the airline had hired for the two told reporters police were linking them to a criminal article related to assistance to a premeditated murder.

"Oedi was in charge of the pantry while Yeti served the food. According to Yeti, she offered a welcome drink to Munir and asked him what food does he want. She took the food randomly and there was nothing unusual with it," said lawyer Mohammad Assegaf.

"Police are accusing them of assistance to murder. I don't see any reason for them to be suspects," he said.

Last month police had named Garuda pilot Pollycarpus Budihari Priyanto, who was assigned to supervise security on the September 2004 flight, as the first suspect in the case that has attracted nationwide attention. He is being held by police.

Under Indonesian law suspects in criminal cases can be held for weeks or months while an investigation is underway before a decision is made on whether to actually bring charges against them.

Munir died on the day the Indonesian parliament approved setting up a truth and reconciliation panel to investigate killings and abductions during the Suharto era.

Munir had also criticised the military's role in separatist hotspots such as Aceh and Papua and had spoken of unknown assailants throwing grenades at his Jakarta office.

His human rights campaigning was recognized with several awards including the Right Livelihood Award, often referred to as the alternative Nobel prize.

Munir was on his way to the Netherlands to study for a master's degree under a scholarship sponsored by the Dutch government. Indonesia was a Dutch colony until 1949 and the two countries still have close ties.