Who Killed Emmett Till?

On September 2, 1955, an editorial letter in the Greenwood Commonwealth claimed that the "State of Mississippi, and Leflore and Tallahatchie counties in particular" had been unjustly blamed for the murder of Emmett Till.  Instead, its author wrote, the citizens of Mississippi were "determined that the guilty parties shall be punished to the full extent of the law." 

More than 50 years later, many argue that not enough was done to find, prosecute, and convict the "guilty parties" in Emmett's Murder. Some still believe that the atmosphere of segregation and prejudice nursed by the citizens of the state of Mississippi helped to encourage, support, and exonerate the men guilty of Emmett Till's murder. 

Who was morally responsible for the murder of Emmett Till?  Was it the entire state of Mississippi, the two men prosecuted, or some other entity?  You will now investigate his case, decide on the guilty parties, and write a persuasive editorial letter to The Greenwood Commonwealth that supports your views.