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.