Michael's bodyguard in Havana

In the American mafia, Michael's bodyguard is what was known as a "zip"-- a Sicilian mafioso brought to America to bolster US interests. The zips lived by older, more brutal codes, and weren't averse to doing things that the US Mafia considered "dirty"-- such as killing women, children, cops, and trafficking in hard drugs. The idea in the US Mafia was that, by importing Sicilian gangsters, they could have things done that their own men would never do, while simultaneously getting to keep their own hands "clean" of the really dirty stuff. (Think Furio on The Sopranos).

The plan ultimately fell apart; the zips proved to be a little too brutal and insular, and were only loyal to/associated with the highest ranks of the US Mafia, resulting in animosity among street level guys. In the Bonnano family, in particular, the Zips were looked down on as a bunch of violent hicks. They also brought a little bit too much of the old country with them and were very public in their murders, such as their penchant for car bombs. Eventually, a large number of them were taken down as a result of their involvement in the heroin trade.