The brazen March murder of a New York Mafia boss was reportedly driven by the young gunman’s delusional obsession with online right-wing conspiracy theories and resulted from his desire to root out and arrest members of the so-called "deep state," according to court papers filed last week.

The papers filed by a defense attorney Friday contain references to QAnon, the deep state, President Trump and the Clintons as part of a bid to have Anthony Comello, 24, declared not guilty by reason of mental defect in the fatal shooting of mob leader Francesco "Frankie Boy" Cali on Staten Island, The New York Times reported.

“He ardently believed that Francesco Cali, a boss in the Gambino crime family, was a prominent member of the deep state, and, accordingly, an appropriate target for a citizen’s arrest,” defense attorney Robert Gottlieb said in reference to his client, according to the paper.

Gottlieb wrote his client’s support for the fringe group QAnon evolved into a delusional obsession, leading him to become convinced that Cali was connected to the deep state -- an undefined cabal of unelected, globalist officials who wield immense power and who, some believe, can control the U.S. government, the paper reported. The 'deep state' does not typically include members of organized crime families.

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The lawyer said Comello also believed he was one of the vigilantes chosen by Trump to bring the group to justice, the paper reported.

“Mr. Comello became certain that he was enjoying the protection of President Trump himself, and that he had the president’s full support,” the Times quoted Gottlieb as writing.

Cali was gunned down in front of his home in March, initially sparking fears of a mob war. Comello was arrested three days later and, during his first hearing, appeared in court with words and phrases associated with the far-right fringe written on his hand.

The Staten Island District Attorney's Office had no comment on Gottlieb's court filing, the Times reported.

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In the papers, Gottlieb said that Comello's QAnon obsession spurred him to attempt several citizen's arrests before the Cali incident, including efforts aimed at New York mayor Bill De Blasio and California Democratic Reps. Maxine Waters and Adam Schiff, according to the paper.

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The attorney also quoted from Comello's Instagram posts, including screeds calling House Speaker Nancy Pelosi a fascist and referring to Bill and Hillary Clinton as “The Clinton Crime Family.”