A judge on Monday afternoon dismissed state felony charges against a private investigator involved in Hewlett-Packard's spy scandal because he already pleaded guilty in federal court to the very same crimes.

Judge Jerome Nadler granted the motion to dismiss all state charges -- identity theft, conspiracy, fraud, and illegal use of computer data -- against Bryan Wagner, according to an Associated Press report.

Wagner and four others working on behalf of HP were charged by the state with breaking the law by improperly obtaining and exchanging personal information.

Wagner worked as a subcontractor and has admitted to creating a fake e-mail account to access detailed phone bills and later destroying his computers when their illicit tactics became public. The case fed interest in congressional hearings on pretexting, which is the practice of pretending to be someone else in order to surreptitiously obtain their private and personal records.

HP executives brought on Wagner and other investigators to figure out who was leaking boardroom information to the media. Those executives have said they had no idea that the investigators stepped outside the law.

So far, Wagner is the only one facing charges in federal court. He entered a plea agreement with federal authorities, who are continuing their investigation.

Wagner's attorney filed a motion to dismiss the state's case in Santa Clara County Superior Court. The lawyer argued that the state could not prosecute Wagner because he has pleaded guilty to similar charges at the federal level. The double jeopardy clause in the Fifth Amendment to the U.S. Constitution bars prosecutors from trying a defendant more than once for the same crime.

The four other defendants have maintained their innocence. They include private investigators Ronald DeLia and Matthew Depante, former HP lawyer and ethics chief Kevin Hunsaker, and former board chairwoman Patricia Dunn, who is battling cancer.

Hunsaker and Dunn are among a group of HP employees and board members who resigned after the company revealed that people working on its behalf might have used questionable tactics while trying to ferret out boardroom leaks.

HP agreed to a $14.5 million settlement the same day California prosecutors filed and dropped civil charges against the company.

InformationWeek associate editor K.C. Jones contributed to this report.