computer rental store owner hugh scrutton is killed when he picks up what appears to be a piece of scrapood. metal shrapnel penetrates his heart and tears off his right hand. 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 for us 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. >> finally on february 20th, 1987, investigators got their first break with the gary wright bombing. >> one of my employees had actually seen a person place this device outside in the parking lot about 25 minutes prior to when i arrived. he stared at her, emotionless, and once he was done pulling the device out of the bag and setting it there, simply got up