Ted or Theodore Kaczynski is mainly a suspect of being the Zodiac Killer because of three things
- living in San Francisco around the time of the murders
- writing letters after committing crimes
- his experience with explosives
Reports do say that Kaczynski is no longer a suspect because of comparisons made to his handwriting and the Zodiac's. They also compared their fingerprints and found proof that he wasn't in California during the times that the Zodiac Killer was active.