The release of Keith Power's article in the San Francisco Chronicle on October 17th 1969 revealed that school bus drivers had been issued with evasion tactics in the event of a Zodiac attack. The article not only released the Zodiac threat on schoolchildren, but stated "Detectives issued an all-points bulletin yesterday, with advice to bus drivers if an attack is, in fact made. The drivers were told to keep the bus in motion "at all costs", instruct passengers to lie on the floor and to attract as much attention as possible with horn and lights". The perceived attack on this school bus in Santa Rosa could easily be attributed to imagination or hysteria, bearing in mind the attention the Zodiac Killer had drawn over recent months. However, the story given by the bus driver becomes more significant when we consider the October 21st 1969 article in the San Francisco Chronicle. It stated "Even before starting on its routes each vehicle has undergone a thorough check to make sure a bomb isn't aboard. Someone hinting he might be Zodiac has telephoned such a threat in Santa Rosa. The man responsible for the safety of the students who ride the buses is Fred Sowash, the district's transportation director. Since last Wednesday (October 15th), when he learned of Zodiac's threat, Sowash has been devoting 18 to 20 hours a day to blunt it".
Law enforcement were skeptical that any shooting took place on a school bus in Santa Rosa on October 17th 1969. If this was the case, then the reported "loud shot" heard by the bus driver just happened to never occur in Santa Rosa, rather than the innumerable other places in the Bay Area.
The threat of "School children make nice targets, I think I shall wipe out a school bus some morning. Just shoot out the front tire + then pick off the kiddies as they come bouncing out", was released in the Los Angeles Times newspaper as early as October 16th 1969, but this information was only made public (at least) one day after the threat on school buses and schoolchildren by the Santa Rosa caller claiming to be Zodiac.