 After his capture , Kaczynski was among the several individuals who had been suspected of being the unidentified Zodiac Killer . Among the links that raised suspicion were the fact that Kaczynski lived in the San Francisco Bay Area from 1967 to 1969 ( the same period that most of the Zodiac 's confirmed killings occurred in California ) , both individuals were highly intelligent with an interest in bombs and codes , and both wrote letters to newspapers demanding the publication of their words with the threat of continued violence toward others if the demand was not met . However , his whereabouts could not be verified for all of the killings , and the gun and knife murders committed by the Zodiac Killer differ from Kaczynski 's bombings , so he was not further pursued as a suspect . Robert Graysmith of San Francisco , author of the 1986 book Zodiac , said the similarities are " fascinating " but undoubtedly purely coincidental . 
