A member of the public would dial the operator and tell them they need police. The operator would then ask for the caller's telephone number and where that caller is calling from in order to ascertain which police department they needed to be connected with.
And so it began! Slover's Incoming call board lit up, which required the dispatcher to plug a lead in to that lighted slot in order to connect with the person calling, which Slover proceeded to do. Now, at this point, the operator is still connected as a 3rd party, a go-between for the member of public and the Vallejo PD dispatcher. The official procedure & legally required step was for the operator to state "Go Ahead Caller..." and then when the operator hears the caller and the Vallejo dispatcher are connected, they were legally required to immediately disconnect from the call. This operator however, broke the law! Slover opened with her standard: "Vallejo Police Dpt..." A second or two thereafter, in reply, a male voice came on the line. A male who spoke in a soft spoken voice & sounding as though he was reading from a rehearsed script, as he said:"I want to report a double murder! If you'll go one mile east on Columbus Parkway to the public park, you'll find kids in a brown car..." At this point, Slover tried to interrupt to get the callers name and location, but when she tried to speak the caller spoke over her: "They were shot with a 9mm Luger. I also killed those kids last year." Then he said tauntingly: Goooooood Byeeeee" Then hung up.
However, unbeknownst to him, instead of the operator disconnecting as required to by law when the two parties are connected (Zodiac & Slover), she stayed connected and had listened to the entire conversation. As stated, before the operator would connect the Zodiac to Vallejo PD, the operator would require him to tell her the telephone number and where he was calling from. Zodiac gave the operator his payphones number, and this is how, almost immediately after Zodiac hangs up, the payphone begins to ring because the operator, illegal as it was to do, had stayed connected and listened in to the entire call - and because she knew and understood the significance of who this caller was, as she'd just heard what he said to Nancy, she took it upon herself to immediately call the number back that Zodiac had given her. This was not overlooked by Zodiac in his letter following the crime, as he refuted the Chronicle's claims of him speeding away, tires screeching, He stated:
"I did not leave the cene of the killing with squealling tires + raceing engine as described in the Vallejo paper,. I drove away quite slowly so as not to draw attention to my car. The man who told the police that my car was brown was a negro about 40-45 rather shabbly dressed. I was at this phone booth haveing some fun with the Vallejo cops when he was walking by. When I hung the phone up the dam X@ thing began to ring & that drew his attention to me + my car."
This was why, in his next call, Dave Slaight recalls the call ending by stating: "Then, all of a sudden heard a clatter, wasn't exactly sure what it was at first, and what He had done apparently is He had just dropped the phone and let it dangle. As I sat there with the open phone (Connection) I could hear voices and traffic in the background. I then began shouting 'Can you hear Me, Can you hear Me?" Zodiac isn't going to make the same mistake twice!
In his call to Slaight, the operator did speak about the caller and stated that she several times asked him for his location and telephone number, but that he would not give it to her, refusing several times and seemed to get rather frustrated with her asking for the telephone number he was calling from. Zodiac had learned from his mistake, and even though he hadn't given this operator his call-box number, he still refused to hang up, just in case!
Below, VPD Police Report Excerpt: At 12:47am Mrs JOHNSON PT&T Operator Called. The Above call was traced to a coin operated telephone at Joe's Union, Tuolumne and Springs Road. The Call was traced by Betty Main whose supervisor would not allow Her to give a statement at this time."
Below: Learning from past Mistakes!
The phone booth as it was discovered and photographed in situ. after Zodiac had used it to call Dave Slaight to report the Lake Berryessa double stabbing. Two months after speaking to Slover, notice how he seems to have learned from his previous experience of what happens if and when you hang up. So, as seen below, he simply drops the handset this time, allowing it to dangle while still connected to the Napa Sheriffs Department and Officer Dave Slaight, the rookie who was filling in for his dispatcher on her break when the call came in.