I am of the opinion that Zodiac stopped writing as frequently to police,and may have stopped killing altogether after the murder of Paul Stine,because he was scared,and he knew he made some mistakes.
October 11,1969,Paul Stine is murdered. Zodiac is spotted by witnesses,and possibly even police.Sketches are made. In addition,there is a print found at the crime scene,but Zodiac doesnt know this yet.
October 13,1969,Zodiac mails a letter boasting to police that he killed Stine,and includes a piece of his shirt as proof. He states that the cops could have caught them had they searched the park properly.He makes NO mention of a patrol car stopping him,and he still doesnt know that they have witnesses and a print.
November 8,1969,Zodiac mails the DRIPPING PEN card.Makes no mention of the Stine killing,nor the witnesses that saw him,or the prints they have,nor the police stopping him.(By the way,this dripping pen card could be a big clue in itself.It was mailed postmarked San Fran. I dont know if police did this,but they should have contacted every Hallmark store,drug store,etc,any place that sold cards,and found out which ones within the San Fran-Vallejo areas carried this card. The card companies name and logo is right on the card. Then they could try to see if they could narrow down where it was sold,and if sucsessful,then interviewed clerks,and review any possible surveillance videos)
Here's about the time that Zodiac gets nervous i believe,and gets scared.
The very next day,November 9,1969,he mails the BUS BOMB letter. He says ,that he has grown angry at the police for spreading lies about him,so he would change the ways he collected souls,and not announce his murders. TRANSLATION: Ive been seeing in the news that you have clues about me and i almost got caught,now i am scared,so i am not going to be writing for a while. He goes on to say,that he looks like the description passed out only when he kills. TRANSLATION: You know what i look like now,but i want you to think that i dont really look like that.He further says,that the prints they found were simply airplane glue over his fingerprints and they dont have his real prints. TRANSLATION: You have my prints,but i want you to think that you dont.If Z used fake prints,or had gloves,why spend the extra few seconds wiping down the cab? He said he wiped it down to leave fake clues,and that the police didnt have any valuable info.I think he did that to make police think that the evidence they had was worthless and not worth pursuing.He also says finally that the police mad a goof,and stopped him that night after the murder.
Another thing he says,which i think is a big clue or mistake by Zodiac,is that his "killing tools" (not sure if he means guns,disguises or what,but i assume its guns)were purchased thru mail order outfits before the BAN went into effect(that's why i believe he means guns). Heres a 1968 GUN BAN link: [ame]http://en.wikipedia.org/wiki/Gun_Control_Act_of_1968[/ame]
This is a slipup by Z. There are two possibilties here:
A- He is tellling the truth.If he is telling the truth,and bought it thru the mail before a gun ban was in effect,police have a date to work with.Simply try to track down purchases thru mail order companies of the specific model guns used by Z prior to the ban.
OR
B-He is lying and he bought his guns locally but doesnt want the cops trying to track him via local gun dealers.
So here you have 2 letters that were sent on back to back days.WHY? Why wouldnt he have just sent one letter.I think he sent the 1st letter,and that day,found out somehow the details of evidence police had against him,and got scared.That is what led him to write the second MISINFORMATION letter the next day trying to convince police that they had nothing.
On December 20,1969(also the anniversary of the faraday/jensen murders),Z sends his next letter to Melvin Belli.This in my opinion,is after a paranoid month getting rid of evidence and waiting for the police to knock on his door. He wants to get a defense in place,as he awaits the police to knock on his door. He reaches out with a nice letter wishing Melvin a HAPPY CHRISTMASS to be pleasant,and even takes the time to write nicely with nice print for a change instead of the sloppy stuff he normally sends(maybe this is even his true handwriting for a change)
Obviously,the police never knocked on his door(unless they did and we dont know it)but Zodiac felt the heat was off,and then wrote again feeling safe a few times in 1970.The next time he sends a confirmed Z letter is the 1974 Exorcist letter.So 4 years with no confirmed letter? What happened during this time. Was he in jail? If he was military,was he shipped out for a while to another base? Had the police finally knocked on his door,and questioned him,thus scaring him so bad that uldnt write for 4 years?