Aussie prime minister Tony Abbott – who opposes capital punishment – now faces the awkward task of fending off requests for the extradition of Sirul Azhar Umar, one of two men condemned over the murder of 28-year-old model, socialite and translator Altantuya Shaariibuu.

According to court testimony, Ms Shaariibuu begged for her life, and that of her unborn child, before she was shot twice in the head, wrapped in plastic explosives, and blown up in a jungle clearing in the suburbs of Kuala Lumpa in October 2006.

Sirul – who flew to Australia in October – is a former bodyguard of Malaysia’s current prime minister, Najib Razak, and one of the key figures in a sensational case involving allegations of high-level corruption and political intrigue.

The Sydney Morning Herald reports that allegations have simmered for years that Ms Shaariibuu was murdered to keep her quiet about alleged payments made to high-level Malaysian officials in connection with the $2bn purchase of two French and Spanish-built Scorpene submarines in 2002. Mr Najib was defence minister at the time, and Ms Shaariibuu worked as a translator during the negotiation process.

French investigators are probing “commission” payments totalling $160m to companies reportedly set up by Abdul Razak Baginda – a friend and adviser to Mr Najib and also Ms Shaariibuu’s lover. Mr Baginda has admitted that she subsequently attempted to blackmail him for $500,000 to remain silent about the submarine deal.

Sirul and a second policeman were convicted of the killing in 2009 but won an appeal in 2013. However, Malaysia’s highest court last week upheld death sentences on the two officers. Both men deny any involvement.