The Zodiac Map Overlay
On January 29th, 1974, the Zodiac mailed his “Exorcist” letter to the San Francisco Chronicle. A copy of that letter is posted below:
Picture Source: Zodiac Killer
The Zodiac’s “Exorcist” letter gave important clues about his identity because he quotes a song from the play “The Mikado” by W.S. Gilbert and Arthur Sullivan. At the bottom of the page however, Zodiac sketches a drawing in black ink:
The Zodiac wanted this sketch published or he threatened to kill again. So what does this sketch represent?
The sketch is a map overlay. The Zodiac had training with
map reading skills. After taking this map overlay and applying it to a map of
I have numbered 1 thru 7 a map legend of how Zodiac applied this overlay to the maps that he used. Let’s look at these points individually:
The Zodiac used position 1 at
The Zodiac used position 2, the single free dot
in the sketch, to align the overlay along the Vallejo and Lafayette axis on the
map.
Position 3 is the Zodiac’s “pin”, a drawing of a
map pin to signify its anchor position on the city of
Position 4 is the Zodiac’s horizontal alignment
anchor point along
Position 5 is the Zodiac’s largest drawing in
the overlay, and it clearly is a representation of the US Navy’s Alameda
Airfield and
Position 6 of the Zodiac’s overlay aligns with
the next key anchor point, the city of
The last overlay position and the most important
one is position 7. The Zodiac drew a black triangle for this position to point
out its importance. Position 7 is in the center of the
Enhancing position 7 on Zodiac’s map overlay gives:
Position 1 gives “
Position 2 gives the US Naval base at
The Zodiac is again telling investigators that
he served in the US Navy by drawing a topographical overlay of the US Navy’s
base at
Zodiac sleuths are invited to discuss this on the forum!
Christopher Farmer
MS, National Security
February 25, 2007
http://www.opordanalytical.com