The Black Hand (2018) online

The true story about the origins of the mafia in America follows Joe Petrosino - nicknamed the "Italian Sherlock Holmes" - an NYPD cop who goes after the ruthless gang in the early 1900s. The thugs (with the calling card black hand) migrated from Italy to America, and kidnapped people to extort money from their families. They were loathed by law-abiding Italian families who were frightened, but nevertheless helped Petrosino behind the scenes