NEW YORK — When Francesco “Frankie Boy” Cali, leader of the notorious Gambino crime family, was gunned down outside his home in Staten Island earlier this year, police assumed it was the work of a hitman.

But lawyers representing the alleged murderer, Anthony Comello, have a different explanation: the bizarre pro-Trump conspiracy known as “QAnon.”

Comello, 24, sought out Cali because he believed he was a member of the “Deep State,” according to his lawyers. He has pleaded not guilty to charges of second-degree murder and two counts of criminal possession of a weapon.

The notion of a “Deep State” cabal is at the core of the QAnon conspiracy. Adherents to the bizarre cult believe there's a vast transnational criminal network that includes Hollywood elites and high-ranking Democrat officials — and that Trump and his supporters are the only ones who can bring it down.

According to defense lawyers, Comello drove his pickup truck to Cali’s residence in Staten Island at around 9:15 p.m. on March 13. He hung around the area, and then backed his truck into Cali’s Cadillac, which was parked outside his home. Cali came outside, Comello introduced himself, and the two men shook hands. The two men inspected the damage on the vehicles, and then Comello informed him that he was there to make a citizen’s arrest, and had brought handcuffs with him, because he believed Cali was a member of the Deep State.

Cali made a “furtive action” with his hand, so Comello reached into his vehicle, grabbed his gun, and shot Cali, according to Robert Gottlieb, his defense lawyer.

Comello had attempted three other citizen’s arrests in months prior. In February, he attempted a citizen’s arrest at New York Mayor Bill de Blasio’s Gracie Mansion in Brooklyn, but was rebuffed by his security detail. He also attempted to make citizen’s arrests of California Congress members Maxine Waters and Adam Schiff, both Democrats.

Around the time that Trump was elected, in November 2016, Comello’s family started to “notice changes to his personality,” according to a motion filed by his lawyer last week. “He began to take an interest in politics, something he had not been previously involved in.” Around five to six weeks prior to the March 2019 incident, Comello had become increasingly vocal about his support for QAnon.

“But Mr. Comello’s support for QAnon went beyond mere participation in a radical political organization,” Gottlieb wrote. “It evolved into a delusional obsession.”

Comello believed that the conspiracy’s eponymous leader “Q” was “communicating directly with him” and that he’d received secret information about the Deep State. “Because of his self-perceived status in QAnon, Mr. Comello became certain that he was enjoying the protection of President Trump himself, and that he had the president’s full support.”

Comello flaunted his obsession with QAnon during a hearing in March, when he showed up to court with QAnon slogans and the words “MAGA forever”scrawled on his hand.

Police have since executed over 37 search warrants associated with the killing, including searching his Instagram accounts, which Gottlieb says showed he’d been corresponding with QAnon-centric profiles. Gottlieb told the New York Times that he’d been going through “thousands of thousands” of online messages and forums that Comello may have engaged with.

He’s asking the judge to order prosecutors to share information about what was found in Cali’s home or car, specifically whether there was a weapon on his person.