Prime Minister Mahathir Mohamad, who ousted Najib in a shock election upset in May, has reopened investigations into 1Malaysia Development Berhad and vowed to recoup money allegedly siphoned off from the fund.

A task force looking into 1MDB said in a statement 408 bank accounts involving funds of about 1.1 billion ringgit (272.4 million dollars) had been frozen.

The frozen accounts included those of 81 individuals and 55 companies believed to have received funds from 1MDB and involved almost 900 transactions between March 2011 and September 2015.

“The accounts were believed to be linked to the misappropriation and misuse of 1MDB funds,” the task force said.

The task force had earlier said it had frozen accounts belonging to the United Malays National Organisation (UMNO), the political party once led by Najib.

The 1MDB, founded by Najib in 2009, is being investigated in no less than six countries for alleged money laundering and graft.

Civil lawsuits filed by the U.S. Department of Justice allege that nearly 4.5 billion dollars was misappropriated from 1MDB.

Media reports said Najib’s stepson, Riza Aziz, has been summoned by Malaysia’s Anti-Corruption Commission (MACC) to give a statement in connection with the probe.

Riza is the co-founder of Red Granite Pictures; a company that U.S. prosecutors say financed three Hollywood films, including the 2013 Martin Scorsese movie “The Wolf of Wall Street”, with funds misappropriated by 1MDB.

However, both Najib and Riza have consistently denied wrongdoing.

Red Granite paid the U.S. government 60 million dollars as part of a settlement of a civil lawsuit in March.