NEW YORK - Roger Ng, the former Goldman Sachs banker convicted for helping loot Malaysia's 1MDB sovereign wealth fund, on Friday sued the government's star witness Tim Leissner for more than $130 million, alleging fraud.

In a complaint filed in a New York state court in Manhattan, Ng accused his former boss of repeatedly lying in order to steal his investments in energy drink maker Celsius Holdings and artificial intelligence company Sentient Technologies.

The complaint said Leissner, a former Goldman partner, stole Ng's money to cover his own defense costs in a related criminal case where he pleaded guilty in 2018, while depriving Ng of funds to defend himself and appeal his conviction.

"Ng is in the unimaginable position of having to defend himself against allegations made by the person who defrauded him and who stole the money that plaintiff Ng needs to defend against those same allegations," the complaint said.

Leissner's lawyers did not immediately respond to requests for comment.

Ng, the former head of investment banking for Goldman Sachs Malaysia, said Leissner's thefts included a $1.25 million Celsius stake now worth more than $130 million, plus $1 million intended to buy half of Leissner's interest in Sentient.

He said it wasn't until May 2021 when Leissner and his wife, the model and entrepreneur Kimora Lee Simmons, were sued by Simmons' former husband, record executive Russell Simmons, that he learned Leissner had diverted the Celsius investment.

In October 2020, Goldman agreed to pay $2.9 billion and its Malaysian unit pleaded guilty to a corruption charge, to settle probes into the looting of billions of dollars from 1MDB and payment of bribes to win business for the Wall Street bank.

A federal jury in Brooklyn convicted Ng in April of conspiring to violate an anti-bribery law and commit money laundering.

Ng faces up to 30 years in prison. He and Leissner are scheduled to be sentenced in mid-February.

Jho Low, a Malaysian financier and suspected mastermind of the looting, was also indicted in Brooklyn and remains at large.

(Reporting by Jonathan Stempel in New York; Editing by David Gregorio)