A federal suit filed Aug. 29 in Newark alleges that a confidential informant was murdered after the Bergen County Prosecutor’s Office blew his cover to organized crime figures.

In Estate of Lagano v. State of New Jersey, 12-cv-5441, the plaintiff claims the county prosecutor and the state Division of Criminal Justice, which set up the informant arrangement, “creat[ed] a dangerous condition” that led to Frank Lagano’s violent death.

Bergen County Prosecutor John Molinelli calls the suit “nonsense,” saying it was calculated to influence a separate proceeding in state court over funds his office seized from Lagano.

Lagano, 71, was shot once in the head on April 12, 2007, outside the Seville Diner in East Brunswick, of which he was part owner. He was pronounced dead less than an hour later. No one has been arrested and the shooting is still under investigation.

According to the suit, the prosecutor’s office arrested Lagano and searched his home in Tenafly on Dec. 1, 2004, in connection with an illegal gambling operation in which more than 40 people were arrested. Sometime after the arrest, the Division of Criminal Justice recruited him as an informant, the suit alleges.

Michael Mordaga, then chief of detectives in the Bergen County Prosecutor’s Office, allegedly ordered Lagano to pay $25,000 to a particular attorney, promising that “90 percent” of his problems would “go away.”

When Lagano refused, unnamed personnel in the prosecutor’s office to disclose to some of Lagano’s co-defendants in the gambling case that he was cooperating, the estate claims.

The estate says it based its allegations “in substantial part” on another suit against the state filed in late 2010 by James Sweeney, a former investigator in the Division of Criminal Justice, since deceased. Sweeney claimed he was fired in retaliation for investigating corruption in an unspecified county prosecutor’s office. He described actions by parties designated “FL” and “MM” that were similar to those attributed to Lagano and Mordaga.

Molinelli says his office conducted an internal investigation after Sweeney’s suit was filed and found the allegations about Mordaga, that he improperly got out the word that Lagano was cooperating, unfounded.

Molinelli says he will seek sanctions against the estate’s attorney, William Buckman of Moorestown, for suggesting that Mordaga was somehow responsible for the murder. “I believe an attorney at law has some obligation to do some due diligence before they put their name on a complaint,” he says. “It is irresponsible pleading and I will ask for sanctions.”

Buckman did not return a call.

The suit also alleges that employees in the prosecutor’s office illegally kept for their own use more than $50,000 seized from Lagano while executing the search warrant of his home. An inventory of items seized from the home and a safe deposit box left out at least $50,000 in cash taken on that date, the suit says.

Molinelli says his office seized more than $150,000 from Lagano and that Buckman is representing the estate in the civil forfeiture case as well. Molinelli’s office charges that the funds are proceeds of an extortion and money-laundering operation and that Buckman has not offered a plausible scenario for how Lagano obtained the money.

By generating unflattering attention for the prosecutor’s office, Buckman “wants to attempt to intimidate my office into settling with the estate,” Molinelli says.

Mordaga is no longer with the prosecutor’s office. A telephone number for him could not be found. A message left with his mother in Paramus was not returned.

A spokesman for the Attorney General’s Office, Lee Moore, declines to comment.