Complex sentence: Many longtime residents knew the Dunes was controlled by the mafia, having been first built with money from it and the Teamsters pension fund, and the implosion signaled the end of significant mafia control and influence in Las Vegas.
Split into simpler sentences: Many longtime residents knew the Dunes was controlled by the mafia, having been first built with money from it and the Teamsters Pension Fund. The implosion signaled the end of significant mafia control and influence in Las Vegas.