A Beatles historian has come across one of the last autographs John Lennon signed before his fatal encounter with Mark David Chapman thirty years ago.
CNBC has learned that rock historian Denny Somach will put the autograph up for sale next week. "We never thought a piece like this would be discovered," says Somach, who is also an avid collector.
CNBC obtained an image of that autograph and what is likely the last known audio recording of Lennon. (You can hear the recording later in this story).