A longtime lobbyist who pleaded guilty to bribing crooked ex-pol Carl Kruger has been spilling his guts about “numerous other persons” under investigation by the feds, bombshell court papers revealed today.

Richard Lipsky “provided substantial assistance” related to “ongoing law-enforcement investigations” in a bid for leniency, according to the Manhattan federal court filing.

Prosecutor Glen McGorty didn’t identify any of the targets by name and redacted the details of Lipsky’s cooperation, but one political insider said the revelation would send tremors through City Hall and the Albany statehouse.

“Anyone who’s ever had any dealings with him is going to be nervous,” the insider said.

Lipsky was busted by the FBI last year as part of what prosecutors called an “extensive investigation” into public corruption.

Days before his arrest, agents executing a search warrant found more than $100,000 stashed in a safe in his apartment, and another $4,000 in “crisp, large denominational bills” stuffed into a suit jacket.

During the raid, he also spoke on the phone to an unidentified “political operative” to spread the word that the feds had closed in, according to court papers.

He pleaded guilty in January to passing as much as $200,000 in bribes to Kruger, then a powerful Democratic Brooklyn state senator who also pleaded guilty to corruption charges and is serving seven years in the slammer.

Lipsky apparently began cooperating sometime after his guilty plea, when he agreed to serve at least four-plus years behind bars.

His defense lawyer didn’t return a request for comment last night, and a spokeswoman for the Manhattan U.S. Attorney’s Office declined to comment.

Lipsky, whose clients included retailers and unions, portrayed himself as a fighter for the “little guy.”

He ran his one-man business without an office, and was frequently seen roaming around the corridors of power with a cellphone headpiece stuck in his ear.

He was linked to the so-called “Four Amigos” of the state Senate who revolted against the Democratic leadership and handed control to the Republicans in 2009.

Three of them — Kruger, Pedro Espada and Hiram Monserrate — have since been convicted on various corruption charges.

The fourth, state Sen. Ruben Diaz of The Bronx, got a $5,000 campaign contribution from Lipsky in 2009, records show.

In 2010, Lipsky also gave $3,800 to embattled Brooklyn Democratic Assemblyman Vito Lopez, who’s the subject of an ethics probe over allegations he sexually harassed female staffers.

Lipsky was initially scheduled to be sentenced in May, but that proceeding was repeatedly postponed and is now set for Friday.

bruce.golding@nypost.com