Pacing the green rubber floor of Sydney's Villawood Immigration Detention Centre is a man who carries a secret so explosive that it holds both sides of Malaysian politics and its media in its thrall.

The former bodyguard to two Malaysian Prime Ministers, ex-police commando Sirul Azhar Umar is a baby-faced killer, convicted of a political murder so gruesome it made a nation shudder.

Now, facing the death penalty in Malaysia, Sirul has brought his secret to Australia in search of political asylum. So far, he is sitting restlessly with the high-risk inmates at the maximum security Blaxland unit in Villawood, keeping his secret to himself.

"I'm not sure If I'm ready to tell all yet," he tells me as we meet for the first time. "I was a member of the police force, we are bound by code of silence."

What Sirul knows, though, has much broader implications than just for him. It has put the already unstable tenure of Malaysia's Prime Minister, Najib Razak, on even shakier ground. It has brought one of Malaysia's ruling elite, Australia's old diplomatic foe, Mahathir Mohamad, out of retirement to speak against his former protege, and it has excited the country's perpetually oppressed opposition with the hope that perhaps after nearly 60 years, the edifice of that country's political dynasty is crumbling.

As Malaysia hangs on his words, Sirul is hoping somehow to trade his secret for a new life in Australia.

The story began at 4pm on October 19, 2006, when Sirul met his police partner Azilah Hadri in the bustling central market of downtown Kuala Lumpur. In the humid marketplace, Azilah told him the the pair had been ordered to eliminate a glamorous Mongolian translator who had penetrated the upper echelons of Malaysia's political elite.

The translator was Altantuya Shaariibuu, the 28-year-old lover of one of Mr Najib's closest advisors. Somebody important believed she knew about corrupt payments to government officials that had emerged out of an international submarine deal.

By 8:30pm on the night the order was issued, the pair had found Ms Shaariibuu and bundled her into a car. By 11pm she was on her knees in the depths of the dense tropical jungle that surrounds Kuala Lumpur, begging for the life of her unborn child.

One shot to the left side of her head should have done it, but her arm kept twitching. Sirul put another bullet through her skull before wrapping her head in a garbage bag to stop the blood soiling the forest floor.

The pair carried her lifeless body deeper into the undergrowth before attaching two sets of C4 explosives to her svelte frame and blowing it out of existence.

A decade later, the man I meet in Villawood seems almost gentle. His hair has greyed around the border of his face, but his face remains youthful.

"I was acting under orders," he insists. "Those people who wanted to kill Ms Shariibuu are still free. I want the chance to redeem my family's dignity ...  I am the scapegoat." Sirul is dangling the possibility of revealing the secret of who issued the order, but says that, under the commando code, "you don't tell".

"At the moment I am grateful for the protection the Australian government has given me, my lawyers have said that I could be able to stay."

He makes a cup of black tea for myself and his mother, Piah Samat, who is all of five foot tall, 74, and has only ever left her village in rural Malaysia a couple of times before.

The tea is bitter – like Sirul, who believes he has become a pawn in a ruthless political game. "He could never have done this himself," his mother says.

She says in his younger days, her son liked nasi lemak and playing soccer. He was the envy of the entire kampung (village) when he was selected for Malaysia's elite special forces.

"But I am glad that he is safe here," she says. "He is honourable, it is his commando code of silence that has kept him from saying anything before".

She has brought him his favourite dish, a fleshy deep crimson beef rendang. It's not your average meal in the barren detention centre – but Sirul is not your average inmate. Sirul took flight as a free man in 2014 before being sentenced by Malaysia's Federal Court to death by hanging. His partner, Azilah Hadri, was led away in shock to death row.

Somehow, the most famous condemned man in Malaysia managed to pass through immigration with his own passport, eventually arriving at a house in Ipswich, Queensland, where his teenage son was living.

In January, Australian immigration officials caught up with him after Interpol issued a red notice for his arrest. 
For the past four months, Sirul has been sitting in his high security cell, looking hopefully through the tall perimeter fence and trusting his lawyer's assurances that he will be granted asylum.

But the reality is that he is likely to remain in legal limbo for the forseeable future, legal experts say. Australia can't extradite him because he is facing the death sentence and they cannot release him into the community because he is a convicted murderer.

Sirul believes his secret might be his ticket to freedom.

Allegations have simmered for eight years that Altantuya Shaariibuu was murdered to keep her quiet about alleged kickbacks to high-level Malaysian officials over the country's US$2 billion purchase of two French and Spanish-built Scorpene submarines when prime minister Najib Razak was defence minister.

Ms Shaariibuu worked as a translator in the later stages of the negotiations by day and was a sophisticated jet-setting party girl by night. She had a relationship with one of Mr Najib's top aides, Abdul Razak Baginda. Baginda was initially charged with abetting the murder but released before any evidence was heard. 

Mr Najib strongly denies ever meeting Ms Shaariibuu or having any link to her and his government denies any wrongdoing in the submarine purchases, which are the subject of an investigation by magistrates in France.

While the controversy has swirled around him, Sirul has remained tight-lipped, fearful of the possible consequences of speaking out, despite repeatedly threatening to do so.

Two months ago, Sirul's mother, sister and a convoy of politicians from the Malaysian opposition party made the journey to Villawood to try to get him to talk.

"It has been a big question for the whole of Malaysia for so many years," said the opposition's foreign affairs spokesman, Dr Syed Azman.

Dr Azman insisted the journey was "for humanitarian reasons," not political gain. But Sirul remained silent, pegging his hopes on asylum.

 

Then, in April, the political manoeuvring went to the next level when the most powerful force in Malaysian politics, retired prime minister Dr Mahathir Mohamad, who ruled Malaysia for 22 years, met with Sirul's mother and called publicly for a full investigation.

Dr Mahathir said Sirul "was acting upon orders and should be given the opportunity to state his case. A policeman does not kill people unless they are given the orders to do so".

The statement from Dr Mahathir directly contradicted his former protege and current Malaysian Prime Minister, Najib Razak, who dismissed the case as "old news" and "utter rubbish".

The calls from the doyen of Malaysian politics come at a time when Mr Najib's tenure is uncertain. The popularity of the Prime Minister is sliding fast, and some believe the Sirul case could be the catalyst for the end of the United Malays National Organisation (UMNO) political dynasty, which has ruled the country continuously since 1957.

The country's controversial 1MDB financial fund is now up to $14 billion in debt, and allegations of improper overseas property purchases by his family and lavish over-spending by Mr Najib's wife, Rosmah Mansor, have simmered.

In April Mahathir publicly called for Mr Najib's resignation, six years after he was instrumental in bringing down former Prime MInister Abdullah Badawi.

"This is the last resort, I have to go public," he said. "The quiet chat is done."

"I am answerable only to the people – not to any one individual," Mr Najib responded to his former master.

But the Malaysian press are now talking. With Dr Mahathir's sudden intervention, a subject that was once restricted to underground blogs has gone mainstream.

All this expectation now hinges on a phone call – arranged by Malaysia's political opposition – that Dr Mahathir is due to make to Sirul in Villawood this month. Mahathir's protection could provide the move needed to get Sirul out of check in Malaysia's game of chess.

For the man in Villawood detention centre, the end game is clear: political asylum in Australia. For Malaysia and its tangled politics, though, almost anything could happen.