A longtime lawyer for Refco Inc. was convicted on conspiracy and fraud charges Friday in a scheme to help owners and executives at the defunct commodities broker steal more than $2 billion by concealing its financial troubles.

After a week of deliberations, a jury of seven women and five men delivered a partial verdict, finding Joseph P. Collins, a one-time Mayer Brown LLP partner, guilty of conspiracy, two counts of securities fraud and two counts of wire fraud. A mistrial was declared on nine other counts.

"We are deeply saddened by the verdict and will appeal," said William Schwartz, a lawyer for Collins.

Collins faces up to 20 years in prison on the fraud counts. Sentencing is set for Nov. 3.

The criminal trial in U.S. District Court in Manhattan lasted about eight weeks.

A spokeswoman for the U.S. Attorney's office in Manhattan declined comment on whether prosecutors would seek a retrial on the remaining counts.

Deliberations appeared to have become heated earlier this week when a male juror sent a note to the court indicating a female juror had threatened to cut off his finger and told him her husband would "take care of you."

Afterwards, jurors said the acrimony was between the two jurors, as one was annoyed by the other pointing his finger at people when he talked. For the most part, deliberations were uneventful, they said.

"Nobody got hurt. There was no bloodshed," said one juror who refused to give her name. "It's not easy to decide someone's fate."

They said the jury was deadlocked 11-1 on the remaining nine counts, and the juror who complained to the court was the holdout.

Prosecutors had alleged that Collins was a key player in helping former Refco Chief Executive Phillip R. Bennett and others hide the commodity broker's dismal financial picture, including hundreds of millions of dollars of undisclosed debt. Bennett pleaded guilty to securities fraud and other charges last year.

The government had alleged that Collins helped Bennett and others engage in transactions that transferred losses and certain expenses off Refco's books to Refco Group Holdings Inc., a company controlled by Bennett and others. As a result, the company's banks, auditors and investors didn't have a true financial picture of the company, including private-equity firm Thomas H. Lee Partners, prosecutors said. THL Partners engaged in a leveraged buyout of Refco in 2004.

The government said Collins made $40 million for his law firm as Refco's outside lawyer and that gave him incentive to lie, starting in 1997.

However, Schwartz, Collins' lawyer, has said Collins believed he was doing honest legal work and was kept in the dark by Bennett and others at the company.

In his opening statement in May, Schwartz said the legal fees, earned over a 10-year period, didn't go directly to Collins, but went to his law firm. He also said the fees from Refco accounted for 1% of the law firm's fees earned during that period.

Mayer Brown has previously said it was cooperating fully with prosecutors. At the time of Collins' indictment in 2007, the law firm said: "Our review of the evidence available to us shows that the firm acted in a professional, competent and ethical manner in its work on behalf of Refco."

Refco sought bankruptcy protection in 2005, shortly after the company announced it had discovered $430 million in debt owed to a private entity controlled by Bennett.

Bennett was sentenced to 16 years in prison last year after pleading guilty to a 20-count indictment.

-By Chad Bray, Dow Jones Newswires; 212-227-2017; chad.bray@dowjones.com