The author of a new book claims he is the son of the notorious Zodiac killer, an unidentified serial killer who terrorised northern California in the late 1960s.
Gary Stewart, who penned The Most Dangerous Animal of All with journalist Susan Mustafa, discovered items of evidence "that conclusively identify his father as the Zodiac Killer" after he embarked on a journey to find his biological father, publishers Harper Collins said in a description of the book.
The book claims to present "forensic evidence" and "a chilling psychological profile" that identifies the killer.
Stewart, vice-president of a chemical cleaning company in Louisiana, is not the first person to claim knowledge of the identity of the elusive criminal. In 1991, a lawyer said he believed his deceased brother, Jack Steadman Beeman, was the murderer. San Francisco police in 1996 investigated links between the Zodiac killer and "Unabomber" Theodore Kaczynski, who killed three people and injured many more with a series of homemade bombs from 1978 to 1995.
The Zodiac killer, who got the title from sending newspapers letters written in code predicting future killings, is thought to be responsible for multiple unsolved murders in San Francisco and California's Bay Area.
The last letter, received in 1969 after a taxi driver was killed, said there would be no more murders.
The case inspired the 2007 film Zodiac, based on San Francisco Chronicle journalist Robert Graysmith's quest to uncover the identity of the killer.