Working with the Georgia Bureau of Investigation, Kennedy joined the multiple Klan-affiliated organizations under the pseudonym John Perkins in order to gain evidence that could be used to prosecute its members. He obtained information about the Klan's "Invisible Empire" through his own participation and also through a high-ranking informant. As soon as he became aware of new details, he shared the Klan's secrets with police, prosecutors, journalists, and human rights organizations. In 1947, after a year of working undercover, he agreed to testify in a trial against the leaders of the Columbians, Homer Loomis and Emory Burke, who were found guilty.