The construction worker charged in the murder of Gambino godfather Francesco “Franky Boy” Cali seemed unhinged leading up to the brazen hit, friends told The Post on Tuesday.

Anthony Comello — who showed up for his first court appearance Monday with “MAGA forever” and references to the conservative QAnon movement scrawled on his hand — managed the Instagram account “realamericasvoice_” which is filled with anti-Democrat and pro-President Trump posts, said the pals, who spoke on condition of anonymity.

“He had a secret Instagram. He used to post crazy things about politics and Trump and Democrats,” a source said.

The account kicked off in October with a post about Christine Blasey Ford, the sex-harassment accuser of US Supreme Court Justice Brett Kavanaugh.

“Horrible how they can try to ruin a man and his family name and it was all fake just to win. I hope you Dems never get power,’’ raged the writer.

Another post was of Trump and Vice President Mike Pence from Jan. 20 with the caption, “This has been the greatest and amazing two years in this great country (THE UNITED STATES OF AMERICA) for god, for country, for family @realdonaldtrump @vp you rocked the world. We the people are blessed for your SELFLESS PATH FOR THE AMERICAN PEOPLE. THANK YOU.”

The 24-year-old suspect also used the social media platform in his bizarre bid to boot Mayor Bill de Blasio and Gov. Andrew Cuomo out of office.

“He was on Instagram live in front of the mayor’s house a few weeks ago demanding de Blasio comes outside because he was under citizen’s arrest,” a source said. “He was reaching out to people to sign a petition to get the governor and mayor out of office.”

The source said Comello had been messaging him lately to sign the petition.

“I thought he was whacked out so I didn’t call him,” the person said. “In high school, he was a good kid. He hung out with the wrong crowd and did pills and smoked weed and got into fights, but now it’s like he’s someone else. It’s strange.”

Police sources said Comello showed up outside City Hall a few months ago in an attempt to make a citizen’s arrest of the mayor.

Investigators believe Comello may have whacked Cali because the Mafia kingpin barred Comello from dating Cali’s niece.

It’s unclear whether Comello knew whom he was dealing with, one of his friends said.

“I’m not sure if he knew who Cali was but I know that it was over a girl, and if you ask me, he wasn’t all in the head,” said the person. “And it’s sad, because of who he killed, it’s a matter of time before he’s found dead in jail.”

Comello is expected to be extradited to New York to face charges following his court appearance in New Jersey.

His lawyer, Robert Gottlieb, didn’t return messages.