Attorney General Abdul Gani Patail said Tuesday a special taskforce investigating the investment fund 1MDB for alleged impropriety has also seized documents related to 17 accounts at two banks for further investigation.
The taskforce also took documents related to non-compliance with central bank rules by the two banks, he said in a statement that was also signed by the central bank governor, the country's police chief and the head of the anti-corruption agency.
The statement didn't name the banks or say who the accounts belong to. The statement said the frozen accounts belong to "parties believed to be involved in this case." It said the investigation is continuing.
Abdul Gani confirmed on the weekend he had received documents from investigators that link Najib and 1MDB funds. The existence of the documents, which allegedly show $700 million was wired from entities linked to 1MDB into Najib's accounts, was first reported by The Wall Street Journal on Friday.
The documents sent to the attorney general pave the way for possible criminal charges and have embroiled Najib in the biggest crisis of his political career. Najib was already under increasing criticism over his leadership, particularly from his political mentor, former prime minister Mahathir Mohamad.
If charged, Najib would be the first Malaysian prime minister to face a criminal prosecution. His ruling National Front coalition has been in power since independence from Britain in 1957. However, support for the coalition has eroded in the last two general elections. In 2013, it won the polls but lost the popular vote for the first time
Najib has denied taking any money for personal gain and has said the allegations are part of a political plot to remove him. He has said he is consulting his lawyers about the next course of action following the "malicious accusations."
1MDB has said it had never provided any funds to Najib.
The investment fund, set up by Najib in 2009 to develop new industries, has accumulated 42 billion ringgit ($11 billion) in debt after its energy ventures abroad faltered. Critics, led by Mahathir, have voiced concerns about 1MDB's massive debt and lack of transparency.
The Wall Street Journal report said five deposits were made into Najib's accounts and that the two largest transactions, worth $620 million and $61 million, occurred in March 2013 ahead of general elections.
Opposition lawmakers and civil groups on Tuesday repeated calls for Najib to take a leave of absence as prime minister to ensure the investigation can be carried out without fear or favor.
"This has shaken the credibility of the elected government," said opposition leader Wan Azizah Wan Ismail. She said the scandal shows "how rotten governance is in Malaysia."
The opposition will call for a special parliamentary debate, she said.