Police questioned a person of interest Tuesday in connection to the murder of 9-year-old Tyshawn Lee. But the boy’s killing remains unsolved, and that has led to calls for a ceasefire among the gangs. Certain Chicago gangs established a truce in the 1970’s, and then in the 1990’s. But can that work today with so many different gang factions? Two former gang members who helped forge those earlier truces, Wallace Bradley and Floyd Davis, address that question. We also speak with Lance Williams, co-author of “The Almighty Black P-Stone Nation: The Rise, Fall, and Resurgence of an American Gang.” It’s the story of one of Chicago’s African American gangs, co-written by WBEZ’s Natalie Moore.