Mr. Canellas and Mr. Mullikin were named as defendants in a parallel civil case filed by the Securities and Exchange Commission in connection with a 2010 sale of $150 million in bonds by the law firm. Regulators contend that the former Dewey executives participated in a scheme to mislead investors in the bond offering about the financial health of the law firm.
Mr. Mullikin, until a few days ago, was the controller for another large law firm, Paul, Weiss, Rifkind, Wharton & Garrison. Lisa Green, a spokeswoman for the firm, said Mr. Mullikin no longer worked there.
Lawyers for Mr. Canellas, Mr. Mullikin and Mr. Alter declined to comment.
The people briefed on the matter said the two women who had taken pleas and were identified as "Jane Doe" on the court docketing service both worked in the firm's billing and revenue departments.
Prosecutors say the accounting games at Dewey began in November 2008, not long after the merger was completed, and continued until March 7, 2012, shortly before Dewey filed for bankruptcy. The firm found it could not meet provisions in bank loans that required it to meet certain cash-flow projections as revenue slumped badly during the financial crisis. To make it appear as though Dewey was meeting those loan conditions, the top executives schemed to make a series of fraudulent accounting entries that either increased revenue, decreased expenses or appeared to rein in distribution payments to partners, prosecutors said.
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Mr. Vance's office contends that Mr. Davis and Mr. DiCarmine, known as "the Steves" within the law firm, and Mr. Sanders were the architects of that plan, which was intended to keep the law firm afloat long enough for the economy to turn around and revenue to began to pick-up.
One person who has not taken a plea and apparently will not be charged with participating in the accounting scheme is Dennis D'Alessandro, the former chief operating officer at Dewey and part of the executive team that oversaw the firm's financial operation along with Mr. Davis, Mr. DiCarmine and Mr. Sanders.
Bruce Barket, the lawyer for Mr. D'Alessandro, said his client "didn't commit a crime and didn't plead guilty." He added that Mr. D'Alessandro had been extensively interviewed by authorities and would be prepared to testify at trial if subpoenaed.
Still, not all lawyers were critical of Mr. Vance's decision to keep the seven guilty pleas sealed. Marc Mukasey, the lawyer for Dr. Sidney Gilman, the crucial witness in the federal government's successful insider trading prosecution of the former SAC Capital portfolio manager Mathew Martoma, said cooperating witnesses are never eager to see their names in the news.
"In the absence of damage to an ongoing undercover operation, it is highly unusual for the actual guilty plea and the documents that go along with it to remain under seal," said Mr. Mukasey, who heads the white-collar defense practice at Bracewell & Giuliani. "But as a defense lawyer, the longer I can keep my client's name out of the public disclosure, usually the better."
—By Matthew Goldstein of The New York Times