In this excerpt from “Vanguard,” correspondent Christof Putzel speaks with Billy Roper, a leader of the Knights of the Ku Klux Klan. Roper now resides with his family in Harrison, Ark., considered an epicenter for the modern-day Klan. Putzel briefly traces the evolution and history of the Klan in Harrison, and interviews Roper about why he decided to move there, and his plans for keeping the town a white majority.

Self defense or getting away with murder? “Vanguard” returns tonight as Christof Putzel examines controversial “stand your ground” laws in America.