The murderer of Darlene Ferrin made a phone call 40 minutes after the attack, directing officers from the police station to the parking lot at Blue Rock Springs Park. He made the payphone call from the intersection of Springs Road and Tuolumne Street at 12:40 am, stating "I want to report a double murder. If you will go one mile east...... on Columbus Parkway to the public park, you will find the kids in a brown car. They were shot with a 9 mm Luger. I also killed those kids last year.... Good-bye". The overriding impression from the use of language adopted in the phone call, is that of a killer seemingly unaware that the crime has already been discovered by responding police officers. The use of the future tense, with respect to police that "will go" and "you will find," suggests that the Zodiac Killer is of the opinion that his deadly deed is not yet known to police at this juncture.
Bearing in mind his directions are from the police station across the road from the payphone, it could be surmised that the killer has either been somewhere in the vicinity of the payphone or police station for at least 30 minutes, in order for him to have drawn such a conclusion. The only way the murderer could assume nobody had responded to the crime scene from the police station, from which he gave his directions, is by a notable lack of activity in responding police units from this location, This could be in the form of visual confirmation or the audible nature of police sirens. But to know this, he has to be close by - either in his vehicle or residence. We will later give reasons to pour doubt on a killer driving from Blue Rock Springs Park to somewhere close to the payphone or police station, to watch the unfolding activity from the confines of his vehicle. This will further corroborate the likelihood of a killer living extremely close to the intersection of Springs Road and Tuolumne Street, or very close to the police station itself.
Officer Richard Hoffman stated: "I was working as a patrol officer in a juvenile division. It was a plainclothes assignment. I wasn't far away, so I turned around and went back out there (Blue Rock Springs parking lot)". Detective Sergeant Ed Rust stated "My partner and I, John Lynch, who was also a detective sergeant, he was the senior of our team. We worked a late shift, three to midnight, something like that, and I was driving the plainclothes car- we were plainclothes detectives- and we were round the downtown area in Vallejo. It was close to midnight, when we heard reports of a possible shooting at Blue Rock Springs Park over the radio and they had dispatched a patrol car, and I told John "you wanna head out there" and he said "no, it's probably just firecrackers or something". It was actually just after 12:10 am, when Debra, Jerry and Roger had rang in the crime to police dispatcher Nancy Slover. Detective Sergeant Ed Rust continued "So, since I was driving, I started meandering in that direction, and a few minutes later I believe we got another report of shots fired, again at Blue Rock Springs, and the officer Dick Hoffman, patrol officer, got there first and said he had a shooting- two people involved. So then, obviously, I put it in high gear and took off and we got out there pretty quickly".
If he had a visual on the police station from 12:10-12:40 am, one could argue he had seen little activity to suggest the police had discovered the crime in the preceding 40 minutes. Thereby explaining his use of the future tense in his directions to police. Dispatcher Nancy Slover would corroborate this lack of activity in the 2007 'This is the Zodiac Speaking' documentary, stating "At 12:10 am, the first call I received, was from a young white woman in her late teens, and she was really agitated, excited or whatever. She reported that there were kids being shot at at Blue Rock Springs. So, I took the call and I gave it to the dispatcher, and I remember her saying "I don't know who I'm gonna send, because I don't have anybody free".
If the Zodiac Killer had driven to Benicia or Napa, and made the phone call from such a place, would he not have just proclaimed the murders as he did at Lake Berryessa seven weeks later, when he used the phrase "I'm the one that did it", rather than "you will find the kids in a brown car". This is not conclusive proof he was close to the Vallejo Police Station in the 30 minutes after the crime, however, the possibility exists, especially when we consider his August 4th 1969 'Debut of Zodiac' letter, in which he tries to sell us a story.
The police or newspapers have never confirmed the existence a negro male adult reporting his sighting of Zodiac by the Springs and Tuolumne payphone. Therefore, it must be viewed with great suspicion, a killer offering up confirmation that he was in his "brown" vehicle rather than on foot when making the phone call to Nancy Slover. If the Zodiac Killer lived close to the payphone, or close to the police station, he may have naively been expecting some activity in the area of Solano Avenue or Springs Road in the 40 minutes after his crime - particularly in view of increased activity at Blue Rock Springs Park during the July 4th celebrations. He may have expected his crime to have been discovered by now.
The area of Blue Rock Springs was considerably more rural than it is today. Despite this fact, would it be conceivable that the Zodiac Killer just parked up somewhere before he made the call to police. He couldn't be certain his vehicle wasn't spotted exiting the Blue Rock Springs parking lot. He was wearing only a blue t-shirt during the shooting, and had leaned into Darlene Ferrin's passenger side window and over the front seat, to fire the final shots at Michael Mageau. This would have greatly increased the likelihood of blood transfer to his clothing from the window, passenger seat and interior of the brown Corvair. The lighter the t-shirt, the more evident the transfer would have become. Taking these factors into consideration, not withstanding he was still in possession of the firearm, it may have been extremely foolhardy not to have headed straight for home, before heading back to the payphone.
Was the Zodiac Killer's apparent knowledge of the lack of police activity around the police station, the reason for the language adopted in the phone call to Nancy Slover? Of somebody, who knew more than he should have known. The journey time to the payphone from the parking lot is approximately 10 minutes. So why not just make the phone call at 12:10 am and be done with it. Or had he planned to watch the unfolding action from a vantage point close to the police station in fond anticipation of police "running around town". Unfortunately for Zodiac, the wait was seemingly too long.