David Fincher's movie, Zodiac, was based around the real crimes of the Zodiac killer; here's a look at every major suspect in the true crime cases.

The search for the Zodiac killer has been active since the mid 1960s, with many potential suspects that ended up being discredited; the case still remains open today, and became a part of cinema history after being chronicled in David Fincher's movie, Zodiac. Heavily popularized by the media, the case gained public attention due to the letters and cyphers consistently sent to newspapers and police in which the Zodiac would taunt those searching for him and boast about his crimes.

As detailed in Robert Graysmith's true crime book, Zodiac, and David Fincher's film adaptation of the same name, there were many suspects in the case, although none were proven guilty of the murders. Graysmith's favorite suspect was Arthur Leigh Allen, a name now closely associated with the Zodiac due to him being the focus of both Graysmith's book and later on, Fincher's film.

Although investigators only agree on seven confirmed murders, the Zodiac once claimed to have killed thirty-seven people. The two surviving victims of Zodiac's attacks, Mike Mageau and Bryan Hartnell, have offered similar physical descriptions of their assailant, saying that he was heavyset and around five foot nine inches in height. Over time several witnesses have identified multiple suspects, confusing investigators and giving the impression that Zodiac was easily able to alter his appearance.

Arthur Leigh Allen

Heavily favored by cartoonist turned true crime writer, Robert Graysmith, suspect Arthur Leigh Allen became the main focus of his book, Zodiac, which in turn popularized the belief that Allen was the killer. Since a majority of the evidence was circumstantial, such as the Zodiac watch Allen wore and verbal accounts from friend Don Cheney in which Allen detailed novel ideas that bore an eerie resemblance to the killings.

It was also suspected that Allen knew 1969 victim Darlene Ferrin since, according to Cheney, he frequently visited the restaurant where she worked and expressed interest in a waitress there. The case against Allen diminished when his fingerprints and DNA did not match that associated with the killer. Although Allen was identified by surviving victim Mike Mageau, witnesses of the 1969 Paul Stine murder said Allen was not the man they saw. Due to the lack of direct evidence, no charges were brought against Allen in regards to the Zodiac killings.

Ross Sullivan

Ross Sullivan was suspected in the 1966 murder of Riverside City College student Cheri Jo Bates and while the case remains unsolved, it is believed by some investigators that Bates was the Zodiac's first victim. Both San Francisco Chronicle reporter Paul Avery and detective Dave Toschi investigated the Riverside killing in connection to Zodiac.

Ross Sullivan worked at the RCC campus library where the staff described him as an unnerved man with an affinity for dark poetry. A poem written on the bottom of a wooden desk was found in a storage closest at Riverside City College and it described an attack similar to the one on Bates. It was also noted that Sullivan bore a striking resemblance to a 1969 police sketch of the Zodiac killer. RCC staff voiced their concern regarding Sullivan and his behavior, but police claimed he had an alibi for the evening Bates was killed. Sullivan was institutionalized on and off due to mental illness, and died in Santa Cruz in 1977.

Jack Tarrance

In 2007 Dennis Kaufman claimed that his stepfather, Jack Tarrance, was the Zodiac killer. Though Tarrance died in 2006, Kaufman produced several pieces of evidence that he believed incriminated his stepfather in the murders. Tarrance resembled the widely circulated police sketch, matching the descriptions of having a crew cut and glasses. Since it is heavily speculated that the Zodiac had a military background, the physical description matched several suspects, who were confirmed to have spent time in the military. The man described by Bryan Hartnell, survivor of the 1969 Lake Berryessa attack, wore military boots similar to what Tarrance would have worn during his years in the Navy and Air Force.

Kaufman turned over a bloody knife, film rolls, handwriting samples, and a hood that matched the description of the one worn by the Lake Berryessa assailant, but both the DNA and handwriting analyses were inconclusive. Kaufman's claim is discredited by many due to the lack of definitive evidence.

Earl Van Best Jr.

Gary Stewart published his 2014 true crime book, The Most Dangerous Animal Of All, alongside author Susan Mustafa in an effort to name his biological father, Earl Van Best Jr., as the now notorious Zodiac killer. As with Denis Kaufman's claims, authorities and researchers often debunk Stewart's case against his father, citing a lack of direct evidence. Since the Zodiac case remains unsolved, many have claimed to hold a connection to the killer but are unable to deliver substantial proof.

Stewart's evidence was quickly rendered circumstantial, as he relies heavily on Best's physical similarities to the Zodiac, his criminal past and alleged. According to Stewart, his mother attempted to access police files on Best but was turned away due to the extremely upsetting nature of the reports. Stewart believes the concealed files contain connections between his father and the Zodiac killings, but has not provided evidence that would prove his theory.

Richard Marshall

Richard "Rick" Marshall was a radio and movie theater worker who became a person of interest due to overlapping interests with the Zodiac and his proximity to several of the attacks, including Paul Stine and Donna Lass. Marshall's love for the 1907 short film, The Red Phantom (aka The Red Spectre), alarmed investigators as a letter thought to be from the Zodiac was signed "The Red Phantom". Marshall made a compelling suspect due to his knowledge of obscure cinema and the fact that he lived in a basement apartment, a point noted by authorities since several of the Zodiac letters mentioned his basement and they are uncommon in California homes. A character meant to bare similarities to Marshall was dubbed "Rick Martin" and used as a red herring in David Fincher's 2007 film Zodiac, which like its source text, positions Arthur Leigh Allen as the most likely killer.

Lawrence Kane

Lawrence Kane was the primary subject of investigator Harvey Hines's reports who suspected Kane due to his tendency to create aliases (Larry Kane and Larry Cane) and alter his appearance. Hines believed that Kane knew victim Darlene Ferrin after her sisters identified him as someone who scared Darlene. Hines was convinced that Kane followed possible Zodiac victim Donna Lass when she moved to the Lake Tahoe area, and police received a postcard from the Sierra Club referring to a twelfth victim, supposedly Lass. Throughout his reports, Hines notes Kane's introverted personally, his ambivalence towards women, his brain injury, and his tendency to lose control.

Like many other suspects, Kane spent time in the military, specifically serving in the Navel Reserve. Hines also notes that Kane was living close to where Paul Stine was killed and was identified by Kathleen Jones in 1993 as the person who kidnapped herself and her baby in 1970.

Richard Gaikowski

Richard Gaikowski was a initially a person of interest due to his training as a medic and his intentional arrest in 1965. Investigators noted Gaikowski's Army medical training due to the fact that victim Paul Stine's shirt was ripped, a common bandaging tactic taught to military medics. In addition to this, Stine's sister also recalled seeing Gaikowski at her brother's funeral.

Gaikowski had a tendency to shorten his last name to "Gike" or "Gyke", the latter of which can be seen written in several Zodiac cyphers. Police dispatcher Nancy Slover, who the Zodiac contacted after his attack on Darlene Ferrin and Mike Mageau, claimed that Gaikowski's voice matched that of her caller. Gaikowski was committed to a psychiatric ward in 1971 and the Zodiac letters coincidently stopped for almost three years. While Fincher's Zodiac is a strong telling of the case, the mysteries surrounding the actual killer are still very much wide open.

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