1987, he seemed to vanish. >> it's been a year since the unabomber left his angry mark of death. >> after he committed that bombing and that composite was circulated in 1987, he dropped out of sight for six years. >> he could have been incarcerated. he could have had health issues. but you also have to realize it was the first time ever since 1978 he had ever been seen placing a device. so it could have been because he was fearful that he would be caught. >> the unabomber from 1987 to 1993 did nothing. people thought he was dead. but what he was doing, he was really learning how to build better bombs. >> wasn't until june of 1993 that the unabomber surfaced again sending a letter to "the new york times" saying we're the terrorist group fc, we have more