Thanks again both @TB and @H.

Caifano already became famous when his old brother Fat Lenny Caifano (former capo for Giancanas Taylor St crew) was killed by Teddy Roe. From that point on he was constantly on the government's radar and his presence in Vegas was also somehow his "sanctuary" from all of the heat back home in Chicago. But as usual, his reputation quickly reached the west coast too and so by the late 1950s (i think) he was replaced by Roselli.