NEW YORK — The former leader of the New York Senate and his son were indicted May 29 on conspiracy and extortion charges as prosecutors boosted the amount of money from $200,000 to $300,000 that they allege was illegally steered to the son.

The indictment was returned by a grand jury in Manhattan federal court against 67-year-old Dean Skelos and his 32-year-old son, Adam.

The men from Rockville Centre, Long Island, were released on bail earlier this month after they surrendered to face charges that Dean Skelos teamed with real estate developers, an environmental technology company and campaign donors to collect hundreds of thousands of dollars in bribes, gratuities and extortion payments to benefit his son.

Dean Skelos was New York state’s most powerful Republican when he was arrested and accused by prosecutors of taking official actions to secure the money.

Skelos has said he will fight the charges and that he and his son will be vindicated. His son’s lawyer has said Adam Skelos is not guilty

The indictment largely mirrored a criminal complaint that earlier described evidence.

It added to the accusations, though, by claiming that Adam Skelos received more than $100,000 in payments and health benefits from a medical malpractice insurer. The indictment said the insurer provided Adam Skelos with a no-show job while it lobbied his father on legislative matters.

Defense lawyers did not immediately comment on the indictment.

According to court papers, the scheme was carried out since at least 2010. The government said evidence includes court-authorized wiretaps on cellphones used by the father and son. Charges included two conspiracy counts, two extortion counts and two counts of soliciting bribes. The charges carry potential penalties of more than 80 years in prison.

The indictment sought forfeiture of $300,000 from bank accounts held in the name of Adam Skelos and his wife, along with property in Rockville Centre.

Dean Skelos was re-elected majority leader in January after sharing the post with another senator from 2011 to 2013. He stepped down from the position after his arrest and was replaced by another Long Island Republican, Sen. John Flanagan. Skelos, first elected to the Senate in 1984, has retained his legislative seat.

His arrest came four months after federal prosecutors in Manhattan arrested Assembly Speaker Sheldon Silver, a Manhattan Democrat, on charges that he took nearly $4 million in payoffs. Silver also relinquished his position after his arrest, though he retained his Assembly seat. He has pleaded not guilty.

LARRY NEUMEISTER, Associated Press