Heavy metal rocker Ozzy Osbourne is offering a $1,000 reward to the person who can locate his missing briefcase, containing a passport and personal telephone book, his publicist said Tuesday.

The black leather case disappeared sometime between the time Osbourne arrived at O'Hare International Airport in Chicago Monday for a Halloween autograph-signing session at a suburban record store and the time he left Chicago Tuesday.Osbourne, 40, former lead signer of Black Sabbath, just released an album titled "No Rest For The Wicked," No. 17 on the latest Billboard charts.

"The briefcase contained his personal phone book and passport. The case also has a combination lock on it," said a release from his Los Angeles-based promotional company, Jensen Communications. "Any person who can return the case will be awarded with $1,000 reward - no questions asked."

Osbourne, who lives in Los Angeles and England, attended a midnight autograph-signing session Monday at Flip Side Records in Hoffman Estates, where he judged a Halloween costume contest before leaving after 2:30 a.m. Tuesday.

Michael Jensen, head of Jensen Communications, said Osbourne thought he left the briefcase in his limousine, but it was nowhere to be found.

"It's gone," Jensen said. "There was nothing of value inside - just his phone directory and passport."