Zodiac : Arthur Leigh Allen

Though many people have been suspected of being Zodiac through the years, only one, Arthur Leigh Allen (December 18, 1933 - August 26, 1992), was seriously investigated. In July 1971, a friend of Allen's reported his suspicions about him to the Manhattan Beach Police Department, and the report was forwarded to the SFPD. When questioned later, Allen claimed without prompting that the bloody knives he had in his car the day of the Lake Berryessa attack had been used to kill chickens. When asked if he had read The Most Dangerous Game, Allen replied that he had and said it had made an impression on him. This interested the police, as the 408-character cipher appears to allude to that short story.

Allen was the only suspect in the case against whom police had enough evidence to execute not just one, but three search warrants: on September 14, 1972; February 14, 1991; and August 28, 1992, two days after he died. Allen denied his guilt in interviews, but there was much circumstantial evidence against him.

Police found no physical evidence to prove that Allen was the Zodiac Killer, and the Vallejo Police Department chose not to press charges against Allen, even though he was a convicted sex offender and weapons and explosive components were found in his home following the 1991 search. Ultimately, Allen's handwriting did not match the Zodiac's, his fingerprints did not match those suspected to be Zodiac's, no concrete evidence linking him to the Zodiac killings was ever found, and recent DNA testing on suspected Zodiac letters in 2002 did not provide a match. However, neither Vallejo nor SFPD ruled Allen out after the test results.