A mystery unfolding in San Francisco is all about art. A local couple is trying to determine the origins of a sculpture found in their backyard, and they believe there is a good possibility it was created by a well-known Art Deco artist. Greg Gatwood was digging in his Russian Hill backyard in May, doing some landscaping, when he unearthed the sculpture. Stackpole was a renowned muralist and sculptor whose works include the statue in front of San Francisco's old Stock Exchange. The couple is trying to determine why a sculpture was buried in their backyard in the first place, and whether it was simply thrown away or secretly hidden.