The Zodiac Killer
The knife he used was double-edged and about a foot long, possibly a bayonet. It has been described as looking made or repaired by hand, with wooden handle slabs, two brass rivets, and white tape where the guard would normally be.
Hartnell was stabbed six times, and a retired police source confirms a fatal ten times for Shepard, who died of her wounds two days later. Leaving them both for dead, the attacker walked to Hartnell's nearby car and, using a black magic marker, inscribed his crossed-circle logo and the dates of his Bay Area attacks on the door.
Detectives later found a series of clear footprints leading to and from the scene of the attack. The shoes that formed them were determined to have been Wing Walkers, a style of low-cut military boot, size 10 ˝. Set deep in the sand, the prints suggested a heavy man.
Just as he had after the Blue Rock Springs attack, the killer later drove to a pay phone and placed a call through the operator to the local police. The call came through to the Napa Police Department switchboard at 7:40 p.m., a little over an hour after the attack. The call was traced to a pay phone outside a car wash at 1231 Main Street in Napa. As in the case in Vallejo, the booth was near the station.
Evidence technicians later found a clear palm-print on the receiver, the print man was so nervous that he smudged it during the lifting process and any evidentiary value was ruined. In a calm voice, the caller said, "I want to report a murder -- no, a double murder. They are two miles north of Park Headquarters. They were in a white Volkswagen Kharmann Ghia."
When the switchboard operator asked where he was calling from, he said quietly, "I'm the one that did it." Then, perhaps to facilitate a trace or perhaps to avoid the kind of attention he had recounted in his letter to the Examiner, he simply dropped the receiver and walked away, never again to refer directly to this attack.