NEW YORK (Bloomberg) — Former Refco Group Ltd. executive Santo Maggio, the government's star witness in the criminal fraud trial of ex-owner Tone Grant, admitted yesterday that he spent much of his adult life committing fraud.

As Maggio's cross-examination got under way in Manhattan federal court, Grant's lawyer, Aitan Goelman, walked Maggio through the many lies he told to regulators and prosecutors and in depositions and at civil trials over the years. Maggio admitted breaking numerous laws and said he paid illegal bribes when he opened his own firm in 1978, seven years before joining Refco.

"You have been a crook pretty much all your adult life?" Goelman asked. "Yes," Maggio, 56, replied.

The defence is seeking to damage the credibility of Maggio, who's told jurors in recent days about conversations with Grant, a former Yale University quarterback, in which he appeared to know about a fraud at Refco that later cost investors $2.4 billion. Before Goelman began questioning him, Maggio said that Grant telephoned him in 2005 after Refco went public and claimed to have concocted a lie to persuade Soros Fund Management LLC in 1997 not to withdraw $260 million from Refco. To put Soros at ease, Grant denied a rumour that Refco was assuming a customer's large trading losses, though it was true, Maggio said.

"Tone said it was my idea to go to Soros and lie," said Maggio, who on Monday said Refco would have collapsed in 1997 had Soros followed through on its plan to withdraw its money.

Prosecutors say Grant, 64, knew his partner, Refco chief executive officer Phillip Bennett, hid more than $1 billion in losses and expenses through a fraudulent accounting scheme. Grant faces life in prison for misleading Refco's lenders and investors. Grant says he was chiefly a salesman who didn't focus on the details of Refco's accounting and was duped by Bennett, who has pleaded guilty.

Once the biggest independent US futures trader, Refco collapsed in October 2005, two months after raising $670 million in an initial public offering. The New York-based firm filed the 15th-biggest bankruptcy in US history on October 17, 2005, after disclosing Bennett owed the firm hundreds of millions of dollars.

Maggio, who has pleaded guilty to fraud, is testifying for prosecutors in a bid for leniency. On cross-examination, he admitted that he lied to prosecutors and regulators in 2004 in an unrelated matter and in past civil trials while under oath.

"How many times have you taken that same oath and lied?" Goelman asked. "Many," said Maggio, of Naples, Florida.

Goelman asked about prior statements Maggio made that may differ from his trial testimony. The lawyer suggested, for instance, that Maggio, who began cooperating with prosecutors in October 2005, waited two years before telling prosecutors that Grant knew of secret losses suffered by Refco customers in the Asian debt crisis in 1997.

As part of his cooperation, Maggio said he's forfeiting four homes and the rest of his assets, worth $23.3 million. He admitted that his wife has repurchased from the government one of his boats, his interest in race horses and a golf club membership.

Cross-examination will continue today. At the end of his direct examination, Maggio recounted other phone conversations in which he claimed to have told Grant, who was Refco president until 1998, that the firm was "padding" its revenue and had a massive "hole" stemming from unpaid debt. Maggio sold his interest in Refco in 2004.