A federal judge’s decision to toss the guilty plea of Broadcom Corp. co-founder Henry Samueli – in the middle of the trial of another defendant – was highly unusual and has implications for related cases, lawyers unconnected to the case said today.

“I have never, ever heard of this from any judge anywhere in the country,” said Lawrence Rosenthal, a former federal prosecutor who is a professor at Chapman University School of Law in Orange. “It is stunning.”

U.S. District Judge Cormac J. Carney heard Samueli testify over a two-day period this week in the accounting-fraud trial of his former Broadcom colleague, William Ruehle, who was the company’s chief financial officer.

After hearing Samueli’s testimony, and without giving prosecutors a chance to argue, Carney told Samueli on Wednesday that he was setting aside his guilty plea and throwing out the criminal charge against him of lying to the Securities and Exchange Commission.

That the judge would rule based on “the self-serving testimony of a defendant” and without giving prosecutors a chance to present evidence of Samueli’s guilt “is No. 1 on my hit parade of stunning,” Rosenthal said.

John Hueston, a former top federal prosecutor in Orange County who now does white-collar defense work, said Carney’s ruling was “virtually unprecedented and extraordinary.”

“Here, the defense effectively put the government on trial but was aided by some real-time misconduct by the government during the trial itself,” Hueston said.

Carney’s dismissal of Samueli’s case came after he found that federal prosecutor Andrew Stolper had committed misconduct toward another former Broadcom executive, David Dull. Stolper had warned Dull’s lawyers that Dull could face perjury charges if his testimony in Ruehle’s trial was similar to a deposition Dull gave to the SEC.

Carney also granted immunity to Dull and Samueli so that they would testify in Ruehle’s trial and not invoke their Fifth Amendment privilege against self-incrimination. The immunity was requested by Ruehle’s defense. Such requests “are almost never granted,” Hueston said.

“This pro-active judge, combined with events that have unfolded during the trial itself, have created the rare record that I think is fueling these rare outcomes,” Hueston said.

Carney, a former UCLA football player who attended Harvard Law School, was sworn in as a federal judge at the Ronald Reagan Federal Building and Courthouse in Santa Ana in July 2003. He is presiding over all the Broadcom options-backdating cases.

“I do think Judge Carney has an inquiring mind … and is dedicated to pursuing justice in the broadest sense, so he is willing to explore all procedural opportunities to render justice as he sees it,” Hueston said.

On Wednesday, Stolper admitted that he told a journalist about Samueli’s refusal to cooperate with federal investigators in 2007. Such media leaks by prosecutors are “totally improper,” Hueston said.

In dismissing Samueli’s conviction, the judge told Samueli he was “a little bit disturbed by the way the government treated you.”

“All I can tell you at this point is, I’m aware of it, and I’ll take the appropriate action at the appropriate time,” Carney said.

Carney scheduled a hearing for Tuesday on whether to dismiss the case against Ruehle, who is accused of a participating in a conspiracy at Broadcom to backdate stock options given to employees, a practice that led Broadcom to restate earnings by $2.2 billion in 2007.

Lawyers for Henry T. Nicholas III, Broadcom’s other co-founder, who is scheduled to stand trial next year on similar charges related to options-backdating, have watched this week’s events closely.

“There’s no doubt that these events have armed the Nicholas defense camp with a new and powerful defense theme: that prosecutorial misconduct and improper motives have caused a misinformed and unjust criminal indictment,” Hueston said.

Carney in 2008 rejected the agreement between Samueli and prosecutors under which Samueli pleaded guilty and agreed to serve five years probation and make a $12.25 million payment to the federal Treasury. Carney said Wednesday that the agreement gave the “troubling impression that justice is for sale.”

That plea agreement may have been the root of Wednesday’s dismissal, Rosenthal said. “When a ball starts rolling with such an unusual move by the prosecution, you can’t be entirely surprised when things go awry,” he said.

Prosecutors declined to comment.

Today, Ruehle’s defense team rested its case, and jurors were told about Carney’s dismissal of Samueli’s conviction. The jury was told to come back next Thursday, when closing arguments are scheduled in Ruehle’s case – if Carney doesn’t throw out the case first.