BATON ROUGE, La. (AP) — A suspended FBI agent in New Orleans sued the bureau and several superiors Monday for disciplining him after he sent a letter to a federal judge to express concerns about the Justice Department's handling of a case.

Agent Michael Zummer's federal lawsuit accuses the FBI of violating his free speech rights. The suit seeks a court order requiring the FBI to reinstate Zummer's to active duty and restore his security clearance.

Zummer was suspended without pay last September after he sent a letter to U.S. District Judge Kurt Engelhardt about his investigation of a former Louisiana district attorney accused of trading sex for leniency.

Engelhardt sentenced former St. Charles Parish District Attorney Harry Morel to three years in prison last year after the longtime prosecutor pleaded guilty to obstructing the federal investigation.

Zummer's suit said he was "disturbed" by the leniency of Morel's plea deal with prosecutors and wanted the judge to know about his concerns before Morel's sentencing hearing.

In a ruling last September, Engelhardt said Zummer's 31-page letter raised "legitimate concerns" that the Justice Department is either "unable or unwilling" to self-police ethical lapses within its ranks. The judge said he shares Zummer's concerns and found the agent's correspondence to be "particularly interesting (and troubling, to say the least)."

The FBI agreed earlier this year to release a redacted copy of Zummer's letter. His suit asks the court for permission to release the entire text of his letter.

Zummer was assigned to investigate Morel in June 2009. In 2013, Zummer filed an ethics complaint after federal prosecutors initially declined to bring charges against Morel.

Zummer filed the complaint against New Orleans-based federal prosecutor Fred Harper, who once co-owned a condominium with Morel's attorney, Ralph Capitelli.

Harper has said the complaint Zummer filed with the Justice Department's Office of Inspector General "was reviewed by the appropriate authorities and found to be unsubstantiated." Capitelli has called Zummer a "disgraced rogue FBI agent who is trying to desperately salvage his career."

Former U.S. Attorney Kenneth Polite revived the case against Morel after he took office in 2013.

At a news conference after Morel's guilty plea, state and federal authorities accused Morel of being a sexual predator who solicited sex from at least 20 women in exchange for favorable treatment from his office. But they never charged Morel with any sex crimes.

A spokesman for the FBI office in New Orleans said the bureau can't comment on pending litigation or personnel matters.

Last November, Senate Judiciary Committee Chairman Charles Grassley sent a letter pressing Justice Department officials for more information about their response to Zummer's "whistleblowing" claims and his suspension.

"That looks like it could be a misuse of the security clearance process to mask retaliation for protected whistleblowing," Grassley wrote.