A Brooklyn rabbi is being investigated by the state Attorney General’s Office for his connection to 20 nonprofits, some of which have shady financial practices, according to court and tax filings.

Attorney General Eric Schneiderman subpoenaed documents for the groups tied to Yaakov Weingarten, 52, of Midwood.

“The attorney general deems the documents . . . material to an investigation and inquiry undertaken in the public interest,” the June 7 request by Michael Torrisi of the Charities bureau states.

Weingarten’s Attorney filed a petition to squash the subpoena in Manhattan Supreme Court last week, calling the request overly broad and a possible violation of the First Amendment.