Brooklyn Councilman Vincent Gentile has been named in a $10 million suit for creating a hostile work environment for an employee with Asperger's syndrome. View Full Caption DNAinfo/Nicholas Rizzi

BROOKLYN — A city councilman and his staff bullied an aide with autism with pranks such as littering his desk with decapitated stuffed animals and locking him in a basement, a $10 million lawsuit claims.

Michael Bistreich, Brooklyn City Councilman Vincent Gentile’s former legislative and budgetary director, is suing the Bay Ridge politician after he faced “hostile and abusive treatment” during two years in his office, according to the suit filed Tuesday in Manhattan Supreme Court.

"I put my heart and soul into working there and doing my best on everything and it didn't matter," Bistreich, 28, who has Asperger's syndrome, a disorder on the autism spectrum, told the Daily News, which first reported the suit.

"The only thing that mattered was what they felt about me for being different."

Bistreich’s suit alleges that both Gentile — a Democrat who represents Bath Beach, Bay Ridge, Bensonhurst and Dyker Heights — and his chief of staff John Mancuso targeted him because of his diagnosis and tormented him with pranks so distressing he was forced to quit his job in June 2016.

Mancuso once organized a mass-decapitation of the stuffed animals Bistreich kept on his desk that he'd told staff members he “identified with and emotionally valued,” the suit says.

Bistreich found his Teddy bears with their heads ripped off — with one mounted on a flagpole — and a stuffed toy dog had been gutted and painted red to seem bloody, according to the suit.

Bistreich was so distressed by the incident that he isolated himself in a conference room while, as he was later told, Mancuso dismantled a “worse” display he had prepared in the basement, according to the suit.

In another instance, Bistreich went into the basement to retrieve something for Mancuso only for the chief of staff to trap him in the dark by locking the door behind him, the suit claims.

The suit also claims the bullying was tolerated and encouraged by Gentile, who laughed and clapped his hands when a staff member compared Bistreich to Avonte Oquendo — the autistic boy who died after escaping his school through an unattended exit — by suggesting Bistreich “test the doors.”

Gentile repeatedly complained about the twitches that are a common symptom of Asperger’s syndrome and demanded Bistreich take medication to control them.

“Can you look into upping your medication?” Gentile allegedly asked. “You annoy me.”

When Gentile rescinded Bistreich’s $6,000 promotion and his title as Legislative Director in June 2016, he cited a recent vacation as the cause, even though the trip had been approved in January, the suit claims.

“Bistreich’s work environment became so filled with hostility and intimidation that he was finally required to remove himself from Gentile’s workplace," the suit asserts.

Mancuso previously made headlines when he unsuccessfully ran for a Staten Island council seat in 2013. He adopted a rescue dog and posed with it while campaigning for animal shelter reform, but returned the animal to the pound shortly after losing the election.

A spokeswoman from the Councilman’s office said in an email, “We take all allegations of discrimination extremely seriously and will review the lawsuit when we are served."