The Zodiac Killer

The Zodiac resurfaced in 1974, when he wrote a series of letters to the Chronicle over a period of six months and with postmarks from around the Bay Area.  Though ultimately identified through analysis of the envelopes and handwriting, these four letters were different from the others in that the author had abandoned his usual salutation ("This is the Zodiac speaking") and signature (the crossed-circle design). 

The first was sent on January 29 from San Mateo or Santa Clara, just south of San Francisco, and referred to the recently released movie The Exorcist as "the best saterical comidy that I have ever seen."  It also included a quote from The Mikado (about a "dicky-bird" whose "blighted affection" drives it to suicide) and an inscrutable drawing that resembled a hieroglyph of some sort.

I saw and think "The Exorcist" was the best saterical comidy that I have ever seen. Signed, yours truley:
He plunged himself into the billowy wave and an echo arose from the suicide's grave
titwillo titwillo titwillo
PS.  If I do not see this note in your paper, I will do something nasty, which you know I'm capable of doing.

Me-37 SFPD-0

In addition to a single 8-cent Eisenhower stamp, the Zodiac had placed on the envelope two USPS stickers: one bore a picture of a clock set to 12:55 or 11:05 with the advice to "mail early in the day," and the other was a reminder to use the recently-introduced ZIP code.  Probably from the same packet, the killer also stuck two short paragraphs about the stamps and their packaging: "Stamps in this book have been gummed with a matte finish adhesive which permits the elimination of the separation tissues .... This book contains 25 -- 8-cent stamps -- four on this pane and seven each on three additional panes.  Selling price $2.00."  Although this letter fell under brief suspicion as a possible forgery in mid-1978, it was verified as genuine by a panel of handwriting analysts from various agencies throughout California.