(CNN) -- Hikers in California have found items that may belong to missing millionaire adventurer Steve Fossett, officials said Wednesday.

Steve Fossett, seen with wife Peggy in a 2006 photograph, disappeared in September 2007.

A weathered sweat shirt, cash and a pilot's license with Fossett's name were found Tuesday near Mammoth Lakes, police Chief Randy Schienle said. The license did not have a photo, he said.

"We're not certain that it belongs to Steve Fossett, but it certainly has his name on the ID," Schienle said.

Fossett, who was 63, was last seen on the morning of September 3, 2007, when he took off from the Flying-M Ranch outside Minden, Nevada, in a single-engine plane.

He said he was embarking on a pleasure flight over the Sierra Nevada mountain range .

A judge declared Fossett legally dead in February. Watch: Police chief describes what hikers found. »

No plane wreckage has been found, but a multi-jurisdictional team would return to the area of the discovery to search by air and on foot, Schienle said.