London-based whistleblower site Sarawak Report has made another revelation of what it claims to be another key document in the 1MDB investigations.

This time, it is purportedly a second letter from Bank Negara Malaysia, signed by the deputy governor of the central bank.

"Appended to the auditor-general’s report and pivotal to his findings is a damning letter from the Bank Negara sent to the Public Accounts Committee (PAC)," the article published today states.

The letter is said to be dated March 23 and Sarawak Report pointed out that this was a second letter sent by Bank Negara to the PAC - the other one was on April 6, which had been previously reported.

The April 6 letter, which was reported by The Wall Street Journal, allegedly confirmed that controversial entrepreneur Jho Low was the sole owner of Good Star Limited, which had received US$1.03 billion from 1MDB.

The new letter exposed by Sarawak Report today supposedly details concerns from Bank Negara about certain questionable fund transfers between 2009 and 2011.

The letter explained why Bank Negara cancelled its permission for 1MDB to send US$1.83 billion overseas.

According to the letter, 1MDB has “misrepresented” the way the money was to be utilised, as part of it purportedly went to Jho Low’s Goodstar instead of its joint venture with PetroSaudi International.

Malaysiakini cannot independently verify if the document published by Sarawak Report is authentic, nor can it report on the contents due to legal restrictions.

The new revelation comes just one day after Sarawak Report published an expose from what it claimed to be in the auditor-general's report, which the government has classified under the Official Secrets Act (OSA).

The website said it would be publishing more details from the auditor-general’s report in the coming days.

Previously, PAC member Tony Pua had taken the committee's chairperson Hasan Arifin to task for editing out information on Good Star Ltd from the PAC report without the committee's approval.

Pua had also urged Hasan to reveal the letter he supposedly received from Bank Negara to prove that he was not shielding Low.