Friday, April 7, 1972 9 p.m. - Isobel Watson, a 33-year-old legal secretary in San Francisco, got off the bus in Tamalpais Valley and began walking up Pine Hill. Out of nowhere, a white Chevy swerved at her. The car stopped and the driver leapt out, exclaiming: "I'm terribly sorry. Please let me drive you home." The driver was in his early forties, about 5'9" and wore heavy black-rimmed glasses. Ms. Watson replied: "No thanks." The man repeated his request in a very concerned voice and was again refused. At this time, the man flew into a rage and, pulling short-bladed knife, began to stab at her back. She let out a series of screams. As a result, lights went on in all the nearby houses. The man raced back to his car and sped off. Watson was rushed to the hospital and treated for her wounds. Ken Narlow of Napa P.D. believed that there was a good chance the attacker was Zodiac, being that he fit all of the previous Zodiac descriptions to a tee and that the attack took place on the weekend.