A city firefighter is set to be arraigned early Sunday on charges he trafficked the deadly drug fentanyl after buying it off the dark Web, authorities said.

Anthony Murino, 45, was busted at his Staten Island home Friday night after an investigation led by the United States Postal Inspection Service. The Department of Homeland Security and The US Drug Enforcement Agency also assisted in the arrest.

The firefighter’s family declined to comment, but neighbors were in disbelief on Saturday.

“It’s totally uncharacteristic of him,” one neighbor said, adding the family is “just really good people.”

Another neighbor said Murino lived with his parents, aunts and brother.

“They’re a really good family. They’ve lived here for a long time,” the person said.