Born on February 24th 1928, died 2006. Jack Tarrance is a late addition to the Zodiac suspect list after his name was promulgated by his stepson Dennis Kaufman in 2007.
He attempted to back up his claims by producing a bloody knife, disturbing images on rolls of film, handwriting samples of his stepfather he claimed were very similar to the Zodiac letters - and more unbelievably - a black executioner's style hood found rolled up and concealed within the confines of an amplifier. It was claimed by Kaufman that this was the modified apparel worn by the Zodiac Killer during the murder of Cecelia Ann Shepard and the attempted murder of Bryan Calvin Hartnell at Lake Berryessa on September 27th 1969.
Jack Tarrance died in 2006, but his history suggests he had previously spent time as a serviceman in the Navy and Air Force, tying in with the military boot impressions (Wing Walkers) worn by the Zodiac Killer during his Lake Berryessa attack in Napa County. Trained as a radio operator, it provided him with the opportunity to learn coding that may have inspired the cryptograms and codes contained in at least eight of Zodiac's communications, and possibly more. The composite sketch, created from the three teenagers recollections overlooking the Washington & Cherry intersection in the moments after the murder of Paul Stine on October 11th 1969, also bore a hauntingly near likeness to Jack Tarrance according to some. However, eyewitness recollections are notoriously unreliable, and the Presidio Heights sketch has been likened to countless individuals. This form of circumstantial evidence used to promote persons of interest is as weak as it gets.
Irrespective of these purported links to Jack Tarrance, Dennis Kaufman has come under widespread criticism for some of his claims and has been roundly discredited by many Zodiac investigators and amateur sleuths. The FBI later performed DNA and handwriting analysis on the items of interest submitted in 2010, but these tests were deemed inconclusive, ruling Jack Tarrance neither in, nor out of the Zodiac mystery. Dennis Kaufman appeared on a Discovery Channel documentary presented by true crime writer Aphrodite Jones in 2010, where he outlined his belief that his stepfather was in all likelihood the Zodiac Killer. The part featuring Kaufman begins at 14.56 into the video.
He recruited Nanette Barto, a court certified forensic document examiner to take a look at Jack Tarrance's handwriting and compare it to the letters written by the Zodiac Killer. (37.11 in video). She thoroughly examined the handwriting exemplars provided and when prompted by Aphrodite Jones, she stated "I think Dennis Kaufman really does have the stepfather of the Zodiac Killer". Unfortunately, Nanette Barto's impartiality has since been called into question in some circles regarding certain aspects of the above suspect. The chances of Jack Tarrance being the Zodiac Killer is practically nil, along with the majority of the persons of interest named in this case.
