Location of the Bomb:

 By this point the Z32 had drawn me into its web.  I had spent hours and hours over a period of weeks and weeks.  Confident that I was on to something, I pressed forward with the next step, actually coming up with a viable location for the bomb.

  Let’s start by bounding the area for the bomb.  We’ll look for bomb locations between 121 degrees 30 minutes west to 122 degrees 30 minutes west and 37 degrees to 38 degrees 30 minutes north.  This is roughly the Bay Area.  The Zodiac provides clues outside of the Z32 proper that will limit this area even further.


  The next step involved trial and error.  I used different encoding schemes to individually generate valid longitude and latitude values.  Ideally I would have liked to use the same encoding scheme, Morse code for instance to generate both the latitude and longitude numeric values.  I might have been able to pull that off in some locations in the world.  However, the difference between the latitude and longitude numeric values for the Bay Area require different encoding schemes for latitude and longitude.

  There are numerous codes that I could have used.  I stuck with the most well-known:  Morse, Bacon’s Cipher 1&2, Baudot, Murray.  There are many more ciphers that may come up with different solutions.  I invite you to try them. 


  I’ll illustrate converting the Z32’s characters to numeric values. What follows is my first attempt to generate a valid longitude value.  I tried Morse code first.

Zodiac Character:  O      F      D      V       T  

Morse code:           ---    ..-.     -..     …-      -

 The next step would be to either count the dashes using dots as delimiters or count the dots using dashes as delimiters. Counting the dashes we end up with 3112.  Counting the dots we get 215.  Neither method works for two reasons:  the values fall out of the acceptable range for Bay Area latitude and the values are nowhere near as accurate as we need to be.  Let’s try a different code.

Zodiac Character:  O          F       D        V         T

Baudot code:       +++--    -++-   +++-   ++-+   +-+-+

  Counting pluses we get: 3232211.   Counting dashes we get 311111.  Accuracy has greatly improved.  But no matter where we put the decimal point ie 32.32211 degrees, we are nowhere near the bay area.

   In fact, no matter what code I tried I could never get anywhere near the bay area.  So I tried a different code.  In the early 1960’s the teletype machine first came into use.  Early teletype machines were used on US Navy ships.  They used a code called ASCII.  ASCII is still in use today on computer systems.  In the 1960’s, ASCII would have been known to but a few manufacturers of teletype machines or sailors that specialized in communications.  Let’s try ASCII:

Zodiac Character:            O        F      D      V       T

ASCII upper case code:  4F      46     44     56      54

ASCII lower case code:  6F      66     64     76      74


  The leading value for ‘O’ in both cases is problematic.  We only want numbers and not characters.  Recall that the Zodiac mentioned that the code used radians.   Radians are an alternative way to express angles.  Instead of the Zodiac character ‘O with a dot in it’ meaning ‘O’ maybe the Zodiac meant ‘zero point.  The solutions would change to 0.46445654 for uppercase and 0.66647674 for lowercase.  Now convert to degrees from radians to get a decimal degrees.  Uppercase equals 26.61139950932 and lower case 38.18630434573.  We certainly have the accuracy that we need!  Neither of these values work for a latitude but the lower case value is well within the Bay Area longitude range!  We can convert this decimal longitude to degrees, minutes and seconds (or DMS) for ease of use: 38 degrees 11 minutes 10.7 seconds.  Again the accuracy is well within the Zodiac’s stated accuracy requirements. 

  We’ll stick with this value for the numeric value in the second line and see what we can figure out for the first line’s numeric value.  The six characters following the filled square are a challenge.  Back to Zodiac rule number one!  The Zodiac wants this puzzle solved.  He doesn’t have to make it easy though.  So he throws a couple of curve balls at us.  In the first 390 characters of the Z408, the Zodiac used a replacement cipher to mask his message. In the Z32, the Zodiac masks the location of the bus bomb by using characters to represent numbers.  Based on what we found with the numeric value in the second line, there is a good chance that the six characters represent the longitude.  The Zodiac ‘made a goof’ (on purpose) by putting the longitude value in front of ‘NORTH’ where the latitude value should be.  The next ‘goof’ as the Zodiac would say are the six characters themselves. There are three non-standard characters.  The backwards K, the crazy J like character and the backwards F.  I lost sleep over these six characters.  Then I realized that all of the standard text characters are ambidextrous, they read the same forward and backwards.  What if Zodiac made all six characters backwards?  If that was the case, then the funny ‘J’ character could be an ambidextrous ‘W’.   Just to explore all possibilities for that crazy ‘J’ character, I tried all likely characters including ‘J’, ‘L’, ‘T’ and ‘W’.  Is there any precedence for Zodiac using a string of backwards characters?  Yes, I believe so.  See if you can find it in one of his previous ciphers.  I’ll clue you in a little later.  We will follow the same technique that we used on the numeric value for the second line.  But since the characters are backwards, we’ll read the value backwards from right to left.

Zodiac Character: O           ﻼ           W       A         M         ᆿ

Baudot code:     --+++    ++-++    +-++-   ----+    ++-+-    -+++-

  Counting pluses (backwards, right to left) we get: 313235.   Counting dashes we get 1215112.  Counting the dashes is a prospective candidate.  A longitude of 121.5112 is accurate and could be in the Bay Area.  Converting from decimal longitude to DMS using Rapidtables we get 121 degrees 30 minutes 40.32 seconds.  At this point let’s see where we are on the map.  Go to the longitude and latitude we have so far: 38 11 10.7 North and 121 30 40.32 West. Pull up Google Earth and zoom in on the Bay Area and see if the location would be within the fuel oil/fertilizer blast area of a moving school bus.  Unfortunately no.  That location is in the middle of a fallow field a few miles south of Walnut Grove, CA.  We will try a different code.  I can tell you that I tried all of the codes mentioned above.  The solutions ended up in the Pacific Ocean, delta sloughs and rice paddies.  Then I tried Bacon’s Cipher. This code was first used in the early 17th century.

Zodiac Character:   O          ﻼ           W         A         M         ᆿ


Bacon’s Cipher:  01101   01001   10100   00000   01011   00101

Counting zeros right to left we get 121812111.  Looks good so far.  Converting to DMS we get 121 48 43.6.  Go back to Google Earth and see where the bomb would be.  Close to the intersection of Highway 12 and Highway 113!   The critics will claim that there will be a virtually unlimited number of workable solutions.  I invite you to follow the stated process.  Use any method that you’d like to generate numeric values from characters in the Z32.  The longitude and latitude of the Bay Area naturally limits the possible solutions.  Restricting the location to where a bomb would take out a school bus reduces the solution sets further.  In the next section, I will discuss why the location that I finally settled on is unique and meets every single clue that the Zodiac made about the location of the ‘Death Machine’!  It even meets some very subtle clues that you may not have considered. 

Supporting Evidence of the Location:

Let’s now step beyond the Z32 itself and look at other clues that the Zodiac provided regarding the location of the bomb.

  1. The location is ideal for the bomb.  The location is within Solano County.  It is a short distance to Zodiac’s confirmed murders.  The Zodiac is likely to have passed this location numerous times when he was looking for victims.  The road is well travelled during the day but not too busy at night.  School buses certainly travel by on weekday mornings.

  2. I won’t get into numerology but the number twelve seems to come up a lot in the clues that Zodiac provided.  The Z32 cipher letter that contains a Zodiac symbol followed by a dash 12 and SFPD =0.  Superficially this is a kill count.  The previous kill count was Zodiac 10 SFPD = 0.  Apparently, the Zodiac killed two more victims.  This poses two problems.  The Zodiac specifically and purposely states that ‘I shot a man in a parked car with a .38.’  But the previous kill count was ten.  That makes eleven not twelve!  The second problem comes in a later letter that has a kill claim.  In ‘The Pines’ letter, the Zodiac claims ‘searching for number 12’.  Again this implies the Zodiac’s kill count is eleven! Many critics of ‘The Pines’ letter doubt the authenticity of the letter precisely for this kill count discrepancy.  Perhaps the 12 in the Z32 letter was a subtle hint at the location of the bomb. The Zodiac’s Phillips 66 map (yes six plus six is twelve, but I promised not to get into numerology) has crosshairs over the top of Mount Diablo.  The numbers 3, 6 and 9 are placed clock-like around the crosshairs.  Strangely, the number 12 has been replaced by 0.

  3. The actual magnetic deviation in the Bay Area in the 1960’s was 17 degrees.  That being said, the tool for navigation at that time was the hand-held magnetic compass.  The magnetic compasses in use by the public at the time have a minor tick mark at 15 degrees.  Fifteen degrees was the common declination in Northern California for finding true north.  Rotate the Zodiac drawn cross hairs on the Philips 66 map left fifteen degrees and the zero line from Mt Diablo lines up with the intersection of Highway 113 where it meets Highway 12.

  4. If the fuel oil/fertilizer bomb was actually put in place (the Zodiac is a little dodgy about this), I believe that he placed it under Highway 12’s Round Hill Creek Overcrossing.  This bridge was replaced in 2003.  Any remnants of the bomb are likely to have been at the very least disturbed.  Despite this, our metal detector helped us find twisted metal and lengths of 12 gauge stranded wire, one piece burned, at a depth of about twelve inches.  Based on the damage done by 50 gallon drums of fuel oil/fertilizer in Oklahoma City, a couple of drums exploding under the overcrossing would have taken out the bridge.

  5. The Zodiac mentions that his bomb was ‘swamped out by the rain’.  Zodiac may have placed his bomb before heavy rains raised the level of Round Hill Creek.  Round Hill Creek is seasonal and dry most of the year at the Highway 12 overcrossing.  The creek bed fills with water after the first rains come in early winter.

  6. After waiting for a month after sending the bus bomb map, a frustrated Zodiac sends a letter that mentions ‘The Mt. Diablo Code concerns Radians & # inches along the radians’.  If the ‘zero with a dot in it character’ means ‘zero point’ then the value that follows must be a radian value.  The character to numeral conversion technique proposed is capable of the level of accuracy stated by the Zodiac.