Controversial Staten Island lawyer Richard Luthmann has been arrested in an 11-count indictment alleging fraud, kidnapping and extortion.

Luthmann and three accomplices were arrested by the FBI Friday morning on charges brought by Acting Brooklyn U.S. Attorney Bridget Rohde.

The indictment alleges that Luthmann acted like a gangster — including recruiting a client who was blind into his criminal scheme.

“As alleged, Richard Luthmann crossed the line from attorney to violent criminal and fraudster,” Rohde said.

The other three defendants are George Padula III, Michael Beck and Stephen Cotogno.

The indictment claims that Luthmann, Padula and another co-conspirator schemed to defraud companies seeking to purchase recyclable scrap metal. As part of the scam, they would ship containers filled with cheap filler material instead of valuable scrap metal.

Luthmann encouraged the co-conspirator to recruit Padula as muscle in the scheme because the co-defendant boasted that his father and uncle were connected to organized crime.

Luthmann, 38, facilitated the fraud by creating and registering bogus companies, including one called Omni Metal Corporation, and recruited a client of his law practice — who was blind and living on public assistance — to be president of the firm.

In another alleged crime, Luthmann was accused of luring an unnamed co-conspirator into a trap, asking him to meet him at his Staten Island law office to sign some paperwork.

Instead, co-defendants Padula and Beck showed up and Beck pulled out a gun and complained that the co-conspirator owed him $10,000 — a $7,000 loan plus a $3,000 “vig” or interest payment, the indictment said.

“Luthmann and his co-conspirators cheated scrap metal customers in order to make easy money for themselves, took advantage of a disabled man to conceal their fraud, and used gunpoint extortion to collect a purported debt,” Rohde said.

FBI Assistant Director in Charge William Sweeney said the alleged crimes involving a lawyer are shocking.

“They are even accused of forcing a blind man to take part in their criminal attempt at profiting in business without working for it.”

Luthmann — who once made headlines for challenging a rival lawyer to a duel — was in hot water before Friday’s criminal charges.

A special prosecutor has been investigating complaints that Luthmann created phony Facebook accounts to masquerade as borough politicians and candidates for public office.

Staten Island DA Mike McMahon recused himself from that case because he was the subject of Luthmann’s barbs, spurring the court to appoint a special prosecutor.

In Friday’s criminal case, Luthmann, Padula, 29, and Beck, 59 — all of Staten Island — are charged with kidnapping, extortioniate collection of credit and brandishing a firearm during the commission of those crimes. They are also charged with conspiracy counts.

They face up to life imprisonment if convicted.

Cotongo, 48, of Holmdel, NJ, faces up to 20 years imprisonment for wire fraud conspiracy as part of the criminal enterprise.

The FBI and the US Commerce Department head spearheaded the probe against Luthmann.

Luthmann could not be immediately reached for comment.