The Malaysian Anti-Corruption Commission (MACC) has reassured free, transparent and professional investigation into the SRC International and RM2.6 billion fund case.

MACC Special Operations director Datuk Bahri Mohamad Zin said the investigation would be based on the guidance and authority of MACC Chief Commissioner Tan Sri Abu Kassim Mohamed and the MACC top management which was firm, professional and impartial.

"If there is a case, it would be our responsibility to propose charges in an investigation paper which would be forwarded to the Attorney-General next week. So also, if it was the other was around," he said in a statement Sunday.

Bahri said the MACC however, would not allow details of investigations, including the name of the donor of the RM2.6 billion fund to be disclosed.

"The matter was also mentioned by former attorney-general Tan Sri Abu Talib Othman to a portal on Dec 26, 2015, that MACC has no authority until the case under investigation has been brought to court. MACC hopes all will understand the matter," he added.

He was commenting on a statement by PKR vice-president and secretary-general Mohd Rafizi Ramli that MACC needed to reveal the name of the donor who contributed RM2.6 billion to Prime Minister Datuk Seri Najib Razak.

Bahri stressed that the MACC Act 2009 did not allow MACC to make public investigation details.

Earlier, on Aug 5, MACC confirmed the RM2.6 billion fund was channelled into the account of the prime minister by a Middle East donor.

On Dec 5, MACC recorded statements from Najib on SRC and the RM2.6 billion fund issue.

In the meeting lasting over two-and-a-half hours, Najib had given his cooperation to the MACC.

SRC International is a subsidiary of 1Malaysia Development Berhad (1MDB), until it was placed under the finance ministry in 2012.