A judge on Thursday lifted a seal on court records and transcripts that a Southern California man says will prove he was an informant for the FBI.

Craig Monteilh claims he has not been fully paid by the FBI for spying on mosques — an activity that angered the Muslim community and brought accusations that worshippers and clerics were being targeted instead of possible terrorists.

Superior Court Judge Carol Williams Elswick ordered the unsealing of 2007 court records related to a theft case against Monteilh, 47, a fitness consultant from Irvine.

Monteilh said the records include testimony from an FBI agent confirming he worked with the agency as an informant.

It was not immediately clear, however, whether the records addressed the spying claim or when the documents would be available to the public.

"No one has to refer to Mr. Monteilh as the alleged informant anymore," Monteilh's attorney Adam Krolikowski said after the ruling.

In a statement, the FBI said it has "an historic policy of neither confirming of denying the identity of informants; to do so would jeopardize investigations and the personal security of others."

FBI agents and prosecutors say spying on mosques is one of the best weapons to uncover lurking terrorists or threats to national security.

Monteilh claims his spying helped glean information for the FBI about Ahmadullah Niazi, the brother-in-law of Osama bin Laden's bodyguard. But he said he was not properly paid for his work and has filed a claim seeking $10 million in damages.

Niazi, who lives in Orange County, has pleaded not guilty to charges of lying about terrorist ties on his passport and citizenship papers.

In a federal court hearing in Niazi's case, an FBI agent acknowledged using an informant that Niazi had reported to authorities for talking about terrorism.

The agent did not mention Monteilh by name, but police reports indicate Niazi had reported Monteilh to local authorities in 2007 and helped a mosque obtain a restraining order against him.

Since Niazi's hearing, Monteilh has revealed himself as the informant.

Monteilh claimed the FBI failed to pay him $100,000 and provide witness protection as part of an exit strategy from his work.

He also accused the FBI of letting him serve eight months in prison on a grand theft charge he said was related to other work he did for the agency.

In the statement, the FBI said any claim that agents directed Monteilh to break the law is "patently false" and any statement suggesting agents targeted or told others to target individuals because of their religion is untrue.