1MDB today said initial probe by Thai authorities showed leaked email communications from PetroSaudi International (PSI) were tampered with.

The Finance Ministry-owned company said this following the arrest of a former PSI staff Xavier Jutso ( photo ) in Thailand.

" 1MDB notes press reports today on the arrest of a former PetroSaudi staff for attempted blackmail and extortion in relation to proprietary email information belonging to PetroSaudi.

"We further note that initial probes show that some leaked emails were tampered with," it said in a statement today.

1MDB had been embroiled in controversy after a whistleblower site exposed the leaked email communications.

Sarawak Report , based on the email communications, had claimed that PSI was used as a front by 1MDB to channel funds to God Star Limited, controlled by Malaysian billionaire Jho Low, who is close to Prime Minister Najib Abdul Razak's family.

1MDB said it is confident that the truth would prevail.

"1MDB is confident that the lawful authorities will thoroughly investigate, establish the facts and take appropriate action under the law.

"As stated previously, 1MDB pledges its full cooperation with the lawful authorities in their ongoing investigations on this matter," it said.

Sarawak Report in an open letter today insisted on the credibility of the email communications.

"According to the current news reports, they (PSI) are attempting to say that these emails were 'tampered' with and they are adding this to the list of 'crimes', which they are laying at the door of Mr Justo.

"However, there is a mass of corroborative evidence to show that this Swiss/UK based company was involved in the disappearance of nearly US$2 billion of Malaysian public money that went to the company Good Star Limited, whose account resides at RBS Coutts Zurich," it said.