The Zodiac Killer mailed the Bus Bomb Letter on November 9th 1969, opening with the lines "This is the Zodiac speaking up to the end of Oct I have killed 7 people. I have grown rather angry with the police for their telling lies about me. So I shall change the way the collecting of slaves. I shall no longer announce to anyone. When I committ my murders, they shall look like routine robberies, killings of anger, + a few fake accidents, etc". Then on page 6 he gives us the Zodiac crosshairs with five X's marked on the circumference, accompanied by "PS. Be sure to print the part I marked out on page 3 or I shall do my thing". These X's are meant to be the areas he is threatening to target if his demands are not followed. The crosshairs can be spun around and placed over a map to correlate with the attacks at Lake Herman Road, Blue Rock Springs, Lake Berrryessa and Presidio Heights, like so. But this only accounts for four attacks and five murders, when clearly the Zodiac Killer is claiming five attacks and seven murders at this juncture. The additional attack he was claiming, was the August 3rd 1969 double stabbing of Kathy Snoozy and Deborah Furlong in San Jose, to which he added "Aug" on the November 8th 1969 'Dripping Pen' card. Furthermore, the inaccuracy of attempting to transfer the crosshairs from the Bus Bomb Letter, to overlay onto a map, is extremely problematic. The Zodiac Killer had placed very small dots around the crosshairs to represent the numbers on a clock face. Therefore, to be far more accurate, we need to place the perfect circle of a clock face over a map and locate the five X's he has placed around the circumference.
One thing to remember here, is that many people have centered these crosshairs over Mount Diablo, when by November 9th 1969 the Zodiac Killer had never referenced Mount Diablo in any of his communications. We would have to wait until June 26th 1970 for the Zodiac Killer to send us the Phillips 66 Road Map with his crosshairs centered over Mount Diablo. These crosshairs had the numbers 3, 6 and 9 around its face, also suggestive of a clock face. So, although the Bus Bomb Letter crosshairs came with no indication of where they (or a clock face) should be placed, it is apparent in hindsight they were to be placed over Mount Diablo. There is also no indication in the Bus Bomb Letter that we should try in any way to rotate the five X's around to suit our needs. Below, I have placed a clock face over Mount Diablo to locate the positions 6, 8, 9, 10 and 11, marked out by the Zodiac Killer
One thing to remember here, is that many people have centered these crosshairs over Mount Diablo, when by November 9th 1969 the Zodiac Killer had never referenced Mount Diablo in any of his communications. We would have to wait until June 26th 1970 for the Zodiac Killer to send us the Phillips 66 Road Map with his crosshairs centered over Mount Diablo. These crosshairs had the numbers 3, 6 and 9 around its face, also suggestive of a clock face. So, although the Bus Bomb Letter crosshairs came with no indication of where they (or a clock face) should be placed, it is apparent in hindsight they were to be placed over Mount Diablo. There is also no indication in the Bus Bomb Letter that we should try in any way to rotate the five X's around to suit our needs. Below, I have placed a clock face over Mount Diablo to locate the positions 6, 8, 9, 10 and 11, marked out by the Zodiac Killer
Interestingly, the Zodiac Killer was claiming five attacks by November 9th 1969, and positions 1 to 5 are vacant on the clock face. The first X falls over position 6, which heads off towards San Jose, the site of the murders he was claiming just one day earlier. Position 10 on the clock face passes directly over Rodeo, the location where Leona LaRell Roberts was to be abducted from in one month from now, on December 10th 1969 (the date matching the clock face). Position 11 passes directly over Pacific Union College in Angwin - the college significant to the attack at Lake Berryessa on September 27th 1969. Position 8 passes over Oakland, brought into play, when on June 18th 1970 a letter was mailed from somebody claiming to be the Zodiac Killer, enclosing two Oakland A's tickets for Gerald Tagert. Position 9 passes directly over Tamalpais Valley, Isobel Watson (33) had just got off the bus on the evening of April 7th 1972, and was walking home along Pine Hill Road, Tamalpais Valley, Marin County at 9.00 pm, when a light colored vehicle veered towards her, knocking her to the ground. The driver exited his vehicle offering to take her home, but after she had refused his offer of apparent help a second time, the concerned citizen suddenly became enraged, pulling out a knife and stabbing the woman in the neck and shoulder. Her screams alerted the neighborhood, forcing the assailant into a hasty retreat from the scene. She was treated at Marin General Hospital and fortunately survived the brutal attack.
I don't know whether these examples highlighted were the intention behind the five X's on the circumference, but it can be strongly argued, based on the Zodiac Killer's introduction in the Bus Bomb Letter, that he was threatening more attacks without announcing the murders he was to accomplish. The statement next to the crosshairs of "PS. Be sure to print the part I marked out on page 3 or I shall do my thing", suggests that these five X's would be the result of non-compliance, rather than the attacks he had already carried out. The Zodiac is split into 12 signs just like a clock face - beginning at zero degrees longitude - which is maybe why the Zodiac Killer attributed zero to the north face of his crosshairs on the June 26th 1970 Phillips Map. Had the Zodiac Killer originally intended to commit 12 attacks when he began his murderous campaign of terror, thereby completing the circle he had created for himself? Something to which he would later realize was simply unachievable.
I don't know whether these examples highlighted were the intention behind the five X's on the circumference, but it can be strongly argued, based on the Zodiac Killer's introduction in the Bus Bomb Letter, that he was threatening more attacks without announcing the murders he was to accomplish. The statement next to the crosshairs of "PS. Be sure to print the part I marked out on page 3 or I shall do my thing", suggests that these five X's would be the result of non-compliance, rather than the attacks he had already carried out. The Zodiac is split into 12 signs just like a clock face - beginning at zero degrees longitude - which is maybe why the Zodiac Killer attributed zero to the north face of his crosshairs on the June 26th 1970 Phillips Map. Had the Zodiac Killer originally intended to commit 12 attacks when he began his murderous campaign of terror, thereby completing the circle he had created for himself? Something to which he would later realize was simply unachievable.