On September 5, 1976, around 7:00 p.m., Lisa was last seen riding her bicycle in Walnut Creek, California. At the time, she was traveling from her home to a local Bay Area Rapid Transit (BART) station. According to police, s She was expected to go back home by 8:00 p.m., but she never showed up and hasn't been seen since. Shortly after she failed to return home, her parents filed a missing person report with the Walnut Creek Police Department. Three hours after she was last seen, Lisa's bicycle was discovered in a grove of walnut trees at Heather Farms Park close to the Contra Costa Canal. Lisa has not been seen or heard from since she vanished.