To be honest, at night, the mafia had a huge advantage. They simply didn't need to kill Arandor; instead, they could kill Amarant (although Arandor himself ordered the hit on him). Then, no matter what, it would be easy to blame Arandor, and the mafia would be left alone with the king, meaning they would win.
Bow down and hear our cry,
Our earthly rulers falter,
Our people drift and die,
The walls of gold entomb us,
The swords of scorn divide,
Take not thy thunder from us,
Take away our pride.
G.K. Chesterton: English Hymnal