DALLAS (AP) — Fifteen tattered $20 bills recovered from the 1971 D.B. Cooper skyjacking sold Friday for more than 120 times their face value at a Dallas auction.

Heritage Auction Galleries said the bills sold for a total of more than $37,000 — two to three times higher than expected.

Winning bidders paid about $6,500 each for two of the $20 bills. The money has the handwritten initials of investigators who examined the bills, which were found buried in sand in 1980.

Another recovered note, a tiny fragment showing only a portion of the printed San Francisco Federal Reserve Bank seal in the design, sold for $358.

Cooper skyjacked a flight from Portland, Ore., to Seattle, claiming he had a bomb. He released the passengers at a Seattle airport for $200,000, four parachutes and a flight to Mexico.

On that flight, he jumped out with a parachute near the Oregon-Washington line. He was never found.

Brian Ingram of Mena, Ark., consigned the notes to Heritage. He was 8 years old when he found three bundles of deteriorating $20 bills on the shore of the Columbia River near Portland, Ore. The FBI matched the serial numbers and kept 13 bills in case it ever prosecutes the Cooper case.