I'm surprised Cohen wasn't killed when Siegel was. They had to have known that Cohen would be mad about it, and that he would never be willing to work with Dragna. I'm guessing that despite Cohen becoming a problem, he was so much more business savvy than Dragna that they still wanted to keep him alive.
Cohen did go to to the Hotel Roosevelt to challenge the alleged assassins who were said to be there at the time, by firing a couple of shots and told them to meet him outside, a few minutes later police sirens could be heard and Cohen left. During that time Las Vegas gamblers were also betting on Cohen and Dragna with Cohen being the favorite to win. It ended when Cohen went to jail. By this time Johnny Roseli already transferred back to Chicago to help look over L.A. for the mob. When Cohen was released in 1955, both him and Dragna were a lot more peaceful, but Cohen celebrity status rubbed a lot of LA members the wrong way. When Frank DeSimone became the boss he continued hostilities with Cohen and was trying to have Cohen killed.
