Investigations into the RM2.6 billion donation received by Prime Minister Najib Abdul Razak's must be reopened, after a Saudi Arabian minister said that the sum was actually an investment, said a Malaysian Anti-Corruption Commission (MACC) adviser today.

MACC operations review panel member Lim Chee Wee said the recent remarks by Saudi Foreign Minister Adel al-Jubeir show that the "prime suspect's" defence must be verified.

"A proper investigation and assessment for prosecution must entail independent verification of any defence by a prime suspect where one cannot simply accept the word of the prime suspect," Lim told Malaysiakini .

Verification of this defence, he said, requires documentary proof of the fund's source, movements, and return.

As such, Lim welcomed attorney-general Mohamed Apandi Ali's willingness to re-open the probe and urged the top lawyer to approve the MACC's request for Mutual Legal Assistance (MLA) from other countries.

Al-Jubeir was quoted by the New York Times as saying that he believed the RM2.6 billion given to Najib was from a "private citizen" and for an investment in Malaysia.

Apandi however told Sin Chew Daily yesterday that it was a donation and that money had come from one of a late Saudi ruler's sons.

The AG had cleared Najib of any criminal offence in regards to the donation and ordered the MACC to stop investigating the matter.

The top lawyer now says that the graft buster can resume investigations if they have new evidence.

Najib has denied misusing public funds or any wrongdoing in regards to the scandal.

Meanwhile, Lim also responded to Apandi's criticism of him airing his grouses about the probe being dropped to the press.

He said he will be engaging Apandi in his capacity as an MACC Operations Review Panel member, but stressed that access to the media is for all.

"The media is not the exclusive domain of politicians to ventilate their views, the media is a tool for education and debate, and activists, civil society leaders, Bar leaders, academicians, and anyone with a view, should be entitled to speak publicly," Lim said.