Prime Minister Najib Abdul Razak has failed to quell the questions surrounding the murder of Altantuya Shaariibuu, Dr Mahathir Mohamad says.
In his latest blog post, Mahathir said: "Najib rebuts nothing. Beyond saying that the Altantuya case is old, he has rebutted nothing."
The former prime minister argued that the 2006 murder case is still relevant as the two perpetrators were only sentenced to death in January.
"The matter is still current because the hanging is to be now. The two were released before.
"Their acquittal meant the matter was settled. But now they are to be hanged.
"Apparently they acted upon orders. Hanging them would be a travesty of justice," he added.
Mahathir was responding to Najib's FAQ, where the prime minister questioned why "influential individuals (with) many resources" are resurrecting the case and implicating him.
"If they believe (the allegations about Najib's involvement) to be true, why did they not raise it when the issue erupted eight years ago? Why now?" Najib asked.
The prime minister added it was "unfair" to ask the government to reinvestigate the case to find out who ordered the murder when the judicial process had been exhausted.
Two former police commandos, Azilah Hadri and Sirul Azhar Umar, were convicted of the murder and sentenced to death.
The pair was first found guilty by the High Court inShah Alam, but later acquitted by the Court of Appeal.
However, the Federal Court on Jan 13 upheld the prosecution's appeal and convicted the pair. However, the motive of the murder was never established.
Prior to the verdict, Sirul had fled to Australia, where he is currently being held in an immigration detention centre.
Australia does not allow the deportation of those facing the death penalty back to their home countries.
In an exclusive interview with Malaysiakini, Sirul said he acted upon orders and claimed that those with a motive to murder Altantuya were still free.
Mahathir had wanted this claim to be investigated.
Deputy Home Minister Wan Junaidi Tuanku Jaafar yesterday confirmed the police are probing the matter.