CHICAGO (WLS) -- Harry Caray's restaurant has been at the corner of Dearborn and Kinzie for more than 30 years, but owners recently discovered a secret underground vault in the building that has a history of mob ties.Owners have found many historic, hidden gems in the building, including a vault leading to an underground tunnel which was discovered 10 years ago.A little black phone book filled with numbers for mobsters was also found behind a wall. This made sense because the building was once owned by mob boss Frank 'The Enforcer' Nitti and his wife Annette. Nitti succeeded Al Capone when he went to prison. His family still lives in the Chicago area.Recently, while clearing out an unused space in a corner of the basement, Harry Caray CEO Grant DePorter discovered a wall with newer brick apparently closing up another underground vault.Given the building's mobster history, DePorter was immediately intrigued."I went to the Chicago History Museum and they got the plans. This was the vault for the building," said DePorter, who has his own role in infamous Chicago history. He drew worldwide attention 15 years ago by blowing up the so-called Bartman ball that some believe cost the Cubs a chance to go to the World Series.Nitti died in 1943 with several million dollars missing and unaccounted for.If any of the money is behind the bricks, Harry Caray's and the family plan to split it.But that's just one of many possibilities.