CNN Crimes of the Century February 6, 2022 05:10:00
This bomb contains a clue that had become known as the unabomber's signature -- a metal plate stamped with the letters "fc." >> fc became one of the standard ways of us being able to tie in one bombing with another. and over the years, became one of the giveaways that this was a unabomb device. >> but the fc signature shed no light on the identity of the unabomber or even if he was only one person. >> throughout the investigation, one of the main questions was is this a lone actor? or is there a group involved? there wasn't clear evidence, one way or the other, for quite a while. >> reporter: ...