This special edition of Cold Case Files offers an inside look, rarely seen, at an active cold case investigation. We follow Det. Vince Velazquez of Atlanta and Capt. Russell Popham of East Point, Ga., as they work to solve the 1995 rape and murder of 14-year-old Nacole Smith, one of Atlanta's most notorious unsolved crimes. We see Velazquez and Popham hit the streets to question people who might recognize the man in their composite sketch, and obtain DNA samples from potential suspects. "It's almost like the carrot's dangling in front of us, but we just can't catch it," Velazquez says of his painstaking, frustrating search for the killer.