the case is famous for its lack of evidence. a few important clues have arisen, nevertheless. in late 1978, a placard, which had instructions on how to lower the rear stairs of a 727 was found just a few flying minutes north of cooper's projected drop zone. it is believed that this is from the rear stairway of the plane from which cooper jumped. in february 1980, eight-year-old brian ingram found $5,880 in decaying $20 bills on the banks of the columbia river.