SYDNEY — A former policeman convicted over an infamous murder in Malaysia has been released from Australian immigration detention.

In 2006, Sirul Azhar Umar killed 28-year-old Altantuya Shaariibuu -- a model and interpreter linked to ex-Prime Minister Najib Razak.

A former policeman and bodyguard to Malaysia's elite, he fled to Australia in 2015 before his case concluded.

The case gripped Malaysia for years, amid claims of political interference.

For almost nine years, Sirul had been held by immigration authorities after his claim for asylum was rejected in 2019.

His release follows a landmark ruling by Australia's High Court last week that outlawed indefinite immigration detention, prompting the unexpected release of dozens of asylum seekers, some of whom had been held on national security grounds.

The Australian government will not deport Sirul back to Malaysia, due to a longstanding policy of not extraditing people to countries where they face execution.

Ms Shaariibuu, a Mongolian, was found dead in a jungle on the outskirts of Kuala Lumpur in 2006. She had been shot in the head and blown up with explosives.

Sirul and another former police officer Azilah Hadri were convicted over her murder in 2009 and given the death penalty. Both appealed against the verdict, but their sentences were ultimately upheld in 2015.

The two belonged to an elite special unit in Malaysia tasked with protecting top lawmakers - including Najib, who was previously accused of interfering in Ms Shaariibuu's murder investigation.

Najib has repeatedly said that he had nothing to do with her case and that he had never met Ms Shaariibuu.

Abdul Razak Baginda, a former associate of Najib, was also arrested for abetting the murder but charges against him were eventually dropped. He later admitted that he had had an affair with Ms Shaariibuu.

In a cryptic statement, Sirul previously claimed that he was "a black sheep that has to be sacrificed" in the case, prompting a flood of political conspiracies.

Campaign groups have also alleged that Ms Shaariibuu was murdered to keep her quiet about purported kickbacks to high-level Malaysian officials.

Earlier this year, Malaysia's parliament voted to remove the country's mandatory death penalty. The country has had a moratorium on executions for five years.

Azilah, Sirul's co-accused, remains on death row. — BBC