Federal investigators are looking into a former county prosecutor's allegation in a lawsuit that he was fired because he complained about the dropping of an indictment that involved a donor to Republican Gov. Chris Christie.

Bennett Barlyn, a former Hunterdon County assistant prosecutor, said he had a more than hour-long conversation with a criminal investigator for the Department of Justice on Wednesday and provided details of the lawsuit and evidence he has to back up his claims.

Barlyn said the investigator asked him about an allegation in his lawsuit that former county undersheriff Michael Russo told a reporter that Christie would step in and "have this whole thing thrown out" after he was accused of misconduct and indicted by a grand jury in 2010.

Russo has denied making the statement, and Christie, a potential 2016 presidential candidate, has denied any involvement in the dropping of the indictment.

Barlyn reached out last April to New Jersey U.S. Attorney Paul Fishman, whose office also is investigating apparently politically motivated George Washington Bridge traffic lane closures by Christie allies.

Fishman wrote back to Barlyn in June, according to a letter obtained by The Associated Press, saying, "It is not apparent on the face of your submission that there have been potential violations of federal criminal law warranting this Office's review." Fishman directed Barlyn to contact one of the office's investigators "to further assess whether your allegations may implicate such statutes."

A spokesman for Fishman declined to comment on Thursday.

Barlyn said the investigator who met with him, who wasn't the one to whom Fishman referred him, asked about New Jersey's official misconduct statutes and whether there were corresponding federal statutes.

Christie's office did not immediately respond to a request for comment Thursday, but in 2012 it denied any involvement in the case.

"This is conspiracy theory stuff from someone who is obviously casting a wide net with hopes of coming up with a big fish or something," Christie spokesman Michael Drewniak said at the time. "It's nonsense."

Barlyn sued the state and Hunterdon County over his firing, saying he was terminated for suggesting that politics influenced the dismissal of an indictment against Russo, the county's sheriff and one other county official in 2011. Christie is not named in the lawsuit, which seeks damages including lost wages.

The lawsuit says the indictment against then-Sheriff Deborah Trout and the two subordinates was dropped by the state attorney general's office because the investigation exposed the possible involvement of a campaign donor to Christie.

Barlyn, a former state deputy attorney general who worked on the county's prosecution of former NBA star Jayson Williams, says in the lawsuit he argued hundreds of appeals for the attorney general's office in front of the Appellate Division and state Supreme Court and consistently received top performance reviews. His problems began, the filing says, when the attorney general's office stepped in to take over the case against Trout, Russo and investigator John Falat Jr.

The 2010 indictment against the trio charged official misconduct, falsification of employment records and other offenses. Among the allegations in Barlyn's lawsuit was that Falat and Russo produced fake law enforcement ID cards, one of which was given to Celgene Corp. executive Robert Hariri, a contributor to Christie's campaign who served on his transition team. Hariri was not charged.

The attorney general's office took over the case and dropped the indictment several months later, citing "legal and factual deficiencies," an unusual move considering the grand jury had effectively given its stamp of approval. There was no attempt to present the charges again to the grand jury to correct the deficiencies, Barlyn says.

Barlyn was suspended soon after and later was terminated, the result, according to the filing, of his telling county acting prosecutor Dermot O'Grady he felt the dismissal was politically motivated.

Barlyn's meeting with investigators was first reported Thursday by the International Business Times.