Federal prosecutors have long had securities plaintiffs lawyers Melyvn Weiss and William Lerach in their cross-hairs. Now they may have a breakthrough that will enable them to bring charges.

David Bershad, a name partner of the firm Milberg Weiss & Bershad, has agreed to enter a guilty plea to one count of conspiracy as part of a cooperation agreement with prosecutors, according to a number of reports. A hearing in federal district court in Los Angeles is scheduled for later today.

Bershad and Steven Schulman, a former partner, as well as the law firm itself were indicted in May 2006, accused of paying more than $11 million in illegal kickbacks to three people who served as plaintiffs in more than 150 shareholder class actions. Schulman, who has pleaded not guilty, later retired from the firm.

Weiss and Lerach, who left the firm in 2004 to form Lerach Coughlin Stoia Geller Rudman & Robbins of San Diego, have never been charged with any crimes. According to a number of reports, however, the two lawyers have been the primary focus of the long-running federal investigation. The two have denied any wrongdoing, and Milberg Weiss is fighting the charges.

Bershad's cooperation would be a crucial tool for prosecutors. Not only was he a partner privy to the workings of the firm at the highest level but he oversaw finances at the firm. The 2006 indictment says that Bershad signed cover letters falsely describing the purpose of the alleged kickbacks. The firm, the indictment says, "kept cash to make such payments in a safe located in a credenza in Bershad's office."

"I'm not going to say anything,'' Bershad, 67, told Bloomberg News when asked about a plea deal. A spokesman for the Justice Department, declined to comment.

At its peak, Milberg Weiss was the unquestioned giant in shareholder class actions, feasting on any sign of  ineptitude or scandal to wring multimillion-dollar lawsuits from publicly traded corporations for shareholders. Feared and reviled inside the executive suites, the law firm's success prompted Congress to change the law to try to make it harder to bring such suits. Since the indictment, however, the firm has lost clients and lawyers.