PUTRAJAYA (May 22): Former Malaysian Prime Minister Najib Razak was being questioned Tuesday by anti-corruption police about a graft scandal that could lead to criminal charges against him.

He was summoned nearly two weeks after the defeat of his long-ruling coalition in national elections, a loss partly due to public anger over alleged corruption at the 1Malaysia Development Berhad (1MDB), the state investment fund that Najib set up.

US investigators say Najib's associates stole and laundered US$4.5 billion ($6 billion) from the fund, some of which landed in Najib's bank account.

Swarmed by reporters, Najib looked calm and smiled as he was escorted into the agency's building.

Najib has denied any wrongdoing since the scandal erupted in 2015. He sacked critics in his government, including a deputy prime minister and the attorney-general, and muzzled the media to try to survive the fallout.

Najib and his wife have been barred from leaving the country after the new government reopened an investigation into the case. Police have raided his home and other properties linked to him, seizing hundreds of expensive designer handbags and luggage stuffed with cash, jewelry and other valuables.

A government official has said Najib could possibly be detained after giving his statement to Malaysia's Anti-Corruption Commission. Abdul Kadir Jasin, a spokesman for a new government advisory council, said over the weekend that an investigation had already been conducted but was suppressed by Najib while he was in power.

Najib's questioning at the anti-graft agency was specifically over why 42 million ringgit ($14.2 million) was transferred into his bank account from SRC International, a unit of 1MDB, using multiple intermediary companies.

The money was in addition to about US$700 million that US investigators said ended in Najib's bank account.

A new attorney general in 2016 cleared Najib of wrongdoing, saying a particular transfer of US$681 million was a political donation from the Saudi royal family and that most of it was returned.

But new Prime Minister Mahathir Mohamad said investigations showed the wrongdoing at 1MDB were more serious than expected.

Mahathir said former attorney-general Abdul Gani Patail had told him he was preparing to press charges against Najib when he was abruptly sacked in 2015.

Mahathir, who was premier 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 he will face the consequences if found guilty of wrongdoing.

The current attorney general has been put on leave and Abdul Gani was appointed as a member of a new task force investigating the state fund.

The US Justice Department said in a statement that it looks forward to working with Malaysian law enforcement in investigating the 1MDB case.

"The Department of Justice is committed to ensuring that the United States and its financial system are not threatened by corrupt individuals and kleptocrats who seek to hide their ill-gotten wealth," it said. "Whenever possible, recovered assets will be used to benefit the people harmed by these acts of corruption and abuse of office."