All those stories about Hill's brother Chick or Dalitz ordering Siegel's assassination are BS, designed to throw sand in the eyes of investigators. Follow the money: the Flamingo was supposed to cost $1million, came it at $5 million-plus, and lost money when the casino opened in 12/46. Naturally, he (and maybe Virginia) were suspected of skimming construction money, although a lot of the over-run was due to contractors cheating him (he was a lousy businessman). He owed a lot of money to a lot of people, especially the NY Mob. Doesn't matter who the actual triggerman (or men) was (or were)--NY ordered it. I doubt they would have subcontracted the hit to Dragna. He had motive--Siegel was muscling inn on his rackets--but NY had the highest motivation.