It could have been a classic “Mob rub-out,” a new case for the FBI’s Criminal Investigations Division and the U.S. Attorney’s Office. That’s what Mob analysts and anonymous cops quoted in the news media expected. But within a few days of the March 13 shooting death of Francesco “Frankie Boy” Cali, reputed boss of New York’s Gambino crime family, the FBI withdrew from the investigation, the cops changed their tune and reporters stopped calling gangland talking heads. Instead of a Mob soldier from a rival family or a professional killer, U.S marshals arrested a troubled Staten Island construction worker, Anthony Comello, ...