Richard Chartrand was blown up in his South Lake Tahoe, NV neighborhood by a sophisticated bomb but his killers were never caught.
It's current owner, attorney Mike Laub said last Thursday crews discovered a secret four foot safe behind the walls, completely sealed off.
He told KSDK: "There is a pirate part of your personality that hopes to find diamonds and gold."
"I can't go anywhere without being stopped and asked what is inside the safe. I had no idea this would become such a distraction."
Twenty different locksmiths from around the county have called to try and unlock it but of the three who have seen it already, none have been able to crack it.
But it's hoped that inside, maybe crucial information about the Chartrand murder, more than 42-years ago.
Laub said: "After the murder it was a conclusion that was drawn in the law firm, Mr. Chartrands personal attorneys, that he had been hit by a New York mob gang or group."
If the safe contains new evidence, the cold case could be blown wide open.
He added: "Every opportunist in the country is trying to get at this."
Laub plans on opening the safe within the next few days, with investigators watching.