Charges were dismissed Thursday against six associates of trial attorney Pierce O’Donnell who were accused of conspiring to launder $25,000 in campaign contributions to Los Angeles Mayor James Hahn’s 2001 mayoral campaign, according to an attorney in the case.

O’Donnell, also a defendant in the criminal investigation by the District Attorney’s Office, was not dismissed from the case.

Judge Ann Jones disagreed with O’Donnell’s argument that the District Attorney could not bring charges in a case that essentially involved violations of the city’s charter. Another O’Donnell associate also remains in the case.

But the judge dismissed the charges against five of his associates because their immunized testimonies were improperly used against them by county prosecutors.

Michael Proctor, an attorney who represents the sixth associate, O’Donnell’s secretary, said his client was dismissed because “aiding and abetting” charges could not be used under the state’s Political Reform Act. But the immunity issue was apparent in the cases of the other associates.

“If this matter had been handled by the U.S. Attorney’s Office, different choices would have been made with regard to immunized testimony used,” Proctor said. “The U.S. Attorney’s Office, as a matter of policy, would not have made the tactical decisions that have come back to roost.”

O’Donnell’s attorney, George O’Connell, did not return calls.

District Attorney Steve Cooley issued a statement soon after the decision, applauding the judge for not dismissing the case against O’Donnell.

“The prosecution of attorney Pierce O’Donnell on misdemeanor criminal charges for allegedly making illegal contributions to Mayor James Hahn’s 2001 campaign is well founded in the law,” the statement said.

Cooley disagreed with the judge’s decision to dismiss the six associates, however, and is considering an appeal. “We will continue to follow office policy in taking statements from potential witnesses.”