Graysmith is best-known for his writings on the Zodiac Killer case. He first became involved in that case when he was a cartoonist for the San Francisco Chronicle during the period in which the Zodiac Killer was active. Although his conclusions are controversial, the New York Post contacted him for his insights when a copycat shooter, Heriberto Seda, was active in New York in the early 1990s. Graysmith blames the Zodiac murders on onetime suspect Arthur Leigh Allen. Graysmith based his book and case on actual police files.
Two films have been based on his books: Auto Focus and Zodiac. Graysmith is portrayed in the film Zodiac by Jake Gyllenhaal.
Graysmith was born in Pensacola, Florida as "Robert Gray Smith." Before his divorce from his first wife, Margaret Ann, they had two sons together, David and Aaron. After the divorce, he changed his name to Graysmith in 1976. Graysmith met his second wife, Melanie, an artist at the Chronicle. They had a daughter together, named Margot Alexandra. They separated in 1980 and divorced in 1983.
