D.B. Cooper; Missing Mustangs; Bayou Sinkhole

An investigation into the 1971 disappearance of airplane hijacker D.B. Cooper, who parachuted from Northwest Airlines flight 727 with $200,000 and was never seen or heard from again. Also: the case of a toxic sinkhole that's threatening to swallow an entire Louisiana town; and criticism over a U.S. government roundup of wild horses in the West.