Some people also believe that the attacker at Lake Berryessa intended to leave at least one victim alive (in this case Bryan Hartnell), because murdering both would have negated the wearing of the costume. This argument carries no weight whatsoever. Bryan Hartnell was bound hand and foot approximately 510 yards from the nearest roadway (Knoxville Road), and was brutally stabbed in the back six times, which resulted in extensive blood loss. In the 2007 Zodiac documentary he recalled the memories of his fight for life:after struggling to free himself from the clothesline bindings: "So I got up and made it about 5 feet and the sparkles and the darkness came back and I had to drop down immediately to keep from passing out. I'd just lost too much blood and had no energy to move. So I waited a minute, got some more strength, and thought I'm going to have to do this a little slower. I made it another five feet and dropped down myself. So I started just taking 5, 10 feet intervals, and found that if I wasn't trying to walk fast and walked bent over holding my chest and walk slower, I could make more distance in between having to stop and rest. I made it about halfway to the road and saw some lights coming". This is where he was eventually aided by park ranger Dennis Land.
It is clear that the Zodiac Killer (or copycat) intended to kill both Cecelia Shepard and Bryan Hartnell - and thought he had - evident by the payphone call placed in Napa approximately 70 minutes later, in which the killer stated "I want to report a murder, no, a double murder. They are two miles north of Park Headquarters. They were in a white Volkswagen Karmann Ghia. I'm the one that did it". So why did the attacker wear a costume with crosshairs on the front if he had no intention of leaving the couple alive?
The Zodiac had every reason to wear the crosshairs symbol, but the copycat didn't.
The attack took place during daylight hours, at 6:30 pm or slightly earlier - so the killer, whether Zodiac or copycat, had good reason to wear a costume or disguise in case he was spotted by any eyewitnesses - something I'm sure he was keen to avoid.
For those in the copycat camp, the writing on the car door of Bryan Hartnell's 1956 White Karmann Ghia and the telephone call to police dispatcher Dave Slaight is not sufficient proof it was the Zodiac Killer, because the style of the handwriting on the car door and composition of the message in the phone call (based on the Blue Rock Springs call) were widely available in many newspapers, and could easily have been reproduced by a copycat. It is therefore imperative we find another reason to tie the Lake Berryessa attack to the Zodiac Killer rather than a copycat.
Bryan Hartnell stated that the assailant wore a black hooded mask made of a cloth material, covering his entire head and shoulders, reaching down to the waist. On the front of the four cornered mask at the chest area was a white circle (3 x 3 inches in diameter) and a symmetrical cross. He would further elaborate on the design of the crosshairs, as well as later in the 2007 Zodiac documentary, stating "It looked like it was made with a machine or with some degree of care- it wasn't just scrawled on with white paint. It was proportional".
The Zodiac Killer had murdered three and seriously injured a fourth person at this juncture, and had bathed in the spotlight of numerous newspaper articles in his name. This must have fed his egotistical nature, and in his own mind, elevated him to another level of self-aggrandizement. The idea that he would then carefully craft a costume befitting of such an infamous and feared villain, doesn't seem that far-fetched. Would a copycat spend this much time creating an elaborate costume bedecked with crosshairs, when nobody was going to be left alive to report their observations to police? It would be a pointless waste of time. A copycat would have just reproduced the handwriting on the car door and made the payphone call. The Zodiac Killer, on the other hand, had every reason to adorn himself with a costume befitting of the man he thought he was.