Former Malaysian Prime Minister Najib Razak was grilled for more than four hours Tuesday over a corruption scandal that could lead to criminal charges against him, while the country's new anti-graft chief said investigations into the case were suppressed by intimidation during Najib's rule.

Najib was summoned by the Malaysian Anti-Corruption Commission (MACC) nearly two weeks after the defeat of his long-ruling coalition in national elections, a loss partly blamed on public anger over alleged graft in the 1Malaysia Development Berhad (1MDB) state investment fund that Najib set up.

According to an investigation by the Wall Street Journal, 42 million ringgit ($10.6 million) originating from SRC International was transferred to Najib's personal bank accounts. It is just one small part in the graft scandal, which is being investigated in several countries. Hundreds of millions of dollars from 1MDB allegedly ended up in Najib's accounts but the ex-leader and the investment vehicle have denied any wrongdoing.

At a news conference, the MACC's new chief commissioner, Mohamad Shukri Abdull, said criminal charges against Najib could come "very soon." In 2015, Shukri led investigations into suspicious money transfers to Najib's bank account. But he flew to the U.S. after Malaysia's attorney general, who was planning to press charges against Najib, was sacked and Shukri heard rumors that he himself would be arrested for an alleged conspiracy to topple the government.

A new attorney general in 2016 cleared Najib of wrongdoing, saying a particular transfer of $681 million was a political donation from the Saudi royal family and that most of it was returned. Shukri said anti-graft investigators were referred to a "questionable prince" from Saudi Arabia who claimed he donated the money to Najib but could not produce any supporting documents.

The former prime minister and his wife were barred from leaving the country after the new government reopened an investigation into the scandal. Police have raided Najib's home and other properties linked to him, seizing hundreds of expensive designer handbags and luggage stuffed with cash, jewelry and other valuables.

New Prime Minister Mahathir Mohamad, who was prime minister for 22 years until 2003 and was spurred out of retirement by the 1MDB scandal, has vowed there will be "no deal" for Najib and that he will face the consequences if found guilty of wrongdoing.

Mahathir has vowed to fully investigate the financial scandal and on Monday the new government set up a task force headed by high-ranking current and former officials to probe the controversy. Following the fall of the corruption-riddled regime, which had led Malaysia since independence from Britain in 1957, figures linked to the 1MDB scandal have been making appearances.

Over the weekend, Mahathir met with Xavier Justo, a former executive of PetroSaudi, a company that was allegedly involved in corrupt deals with 1MDB. The Swiss national is believed to have leaked documents related to the scandal to the media. He was jailed in Thailand for attempting to blackmail his former employer but was released in 2016.