Why The Zodiac Killer Once Left A Note For Police On A Car Door

There was perhaps no greater source of fear on the West Coast from 1968 to 1969 than a chance encounter with the Zodiac killer. While it is likely he had victims before and possibly after this time-frame, these are the years that the killer was known to have been active. Five people are recognized as having been killed by him (though he claimed 37), and despite of the fact that people have survived and witnessed his attacks, no amount of first-hand information has led to his identification. 

Arguably his most infamous attack was that of Bryan Hartnell and Cecelia Shepard in 1969. Adorned in a hood that concealed his face and bore his circle and cross symbol, he approached the pair in their car, bound them, and then stabbed them repeatedly. Shepard died of her wounds, while Hartnell survived to give his account of the event. After committing the murder/attempted murder, the killer then left a message on the door of Hartnell's car that listed the dates of his previous crimes. As put by TheTalko, it is likely that he did so out of amusement; certain that no amount of such clues would be of use.

The Zodiac Killer seems to love the spotlight

The Zodiac Killer was notorious for leaving all manner of clues for police and the media. These ranged from straightforward details of his crimes to plans to construct bombs, to bizarre ramblings. The main source of intrigue in popular culture is the killer's 340 cipher; one of several symbol-laden letters he left to be decoded. This one stood out in the public imagination as it was not decoded until 2020 (via The Washington Post). Conversely, he seldom left any trace of himself, with none of his scarce fingerprints and DNA leading to anything so far (via Medium).

It obviously served him no practical benefit to write his message on Hartnell's car, as this was time he could have spent escaping. Nor was it his most flagrant contact with the police, as he (supposedly) called them via a payphone a few months prior. Yet he did it, evidently, because he could. Even after the murders stopped, he continued to send ominous threats, likely for the purpose of reminding police and the public that he was still out there. While far more quiet killers have been caught in recent years, such as the Golden State Killer in 2018, there is no guarantee the Zodiac killer will similarly be brought to justice.