A crime was six months in the making, incorporating features from both of these attacks, when Robert Michael Salem was knifed to death in his 745 Stevenson Street, San Francisco apartment on April 15th 1970. The killer appeared to mimic the Zodiac Killer's two previous attacks by writing a message at the crime scene, as well as removing something from the victim. However, the attack on Robert Salem was an escalation on the other attacks in regards to the sadistic nature of the crime. The killer had written the message on the apartment wall of Robert Salem in blood and taken the left ear of the victim away from the crime scene (never to be retrieved). By all accounts, the murderer had first attempted to decapitate Robert Salem. The third important facet of this crime, was that it appeared to mimic the meaning behind the Zodiac Killer's last communication on December 20th 1969, when the Melvin Belli letter arrived at 1228 Montgomery Street in San Francisco. The letter mailed to the prominent attorney could have foreshadowed the Robert Salem murder, not only because the killer of Robert Salem was seemingly "losing all control", but because the wording in the Melvin Belli letter appeared to mimic the writing in red lipstick on the apartment wall of Frances Brown, murdered by William Heirens in Chicago in 1945.
The San Francisco murder of Robert Salem seemed like extreme overkill for robbery or revenge, due in large part to the sadistic nature of the crime and the writing in blood on the apartment wall. The killer then took the time to take a shower before leaving. The killer drew an ancient Egyptian ankh symbol on the wall of the apartment, accompanied by the wording "Satan Saves" and the pseudonym "Zodiac". The ankh appears frequently in Egyptian tomb paintings and other art, often at the fingertips of a god or goddess in images that represent the deities of the afterlife conferring the gift of life on the dead person's mummy. If the murderer of Robert Salem was attempting to sidetrack the police investigation and pin this crime on the Zodiac Killer, why didn't he just use the crosshairs symbol of the Bay Area murderer, write on the wall in black marker pen and refrain from decapitating Robert Salem, which would have helped his attempt to frame the Zodiac Killer as being the responsible. This approach would surely have been far easier. Additonally, if the murderer was not the Zodiac Killer, was the killer of Robert Salem just extremely fortuitous in creating a crime scene at 745 Stevenson Street that just happened to mimic two of William Heirens crimes, which may have been mimicked in the Melvin Belli letter - and the last communication mailed by the Zodiac Killer with an item removed from the victim, that of Paul Stine? Or had the killer of Robert Salem worked out the meaning behind the Melvin Belli letter and made the connection to the William Heirens murders in order to mimic them four months later? Could you have imagined the repercussions had it been reported that an ear had been mailed on April 20th 1970 to the San Francisco Chronicle.
The Zodiac Killer mailed the 148 character cipher and letter on or around May 2nd 1971, in which he refrained from taking the easy option of using his Zodiac crosshairs, when he signed his letter using a sun cross from prehistoric cultures. But did he employ the same technique on April 15th 1970, designed to confuse law enforcement until his April 20th 1970 letter arrived, A letter that didn't carry the wording "Satan Saves", but did carry the numerical figure of Jesus, with the added notation of "PS I hope you have fun trying to fiygure out who I killed". The crime scene at 745 Stevenson Street appeared to be the work of a brutal and sadistic killer more in line with a murderer "losing all control" - and in direct contrast with the Zodiac Killer who never went further than necessary in his requirement to murder. Unless of course, the Zodiac Killer took the wording in the Melvin Belli letter seriously and enacted the 1945 murder of Frances Brown in Chicago to the new setting of San Francisco. He certainly liked his history.