Soon after Zack came to Santa Barbara, Eden Capwell Castillo was brutally raped by a man wearing a ski mask. She was taken to the clinic, where Zack examined her. Later, a nurse named Wendy was raped by the same man who had raped Eden. The attacker became known as the Video Rapist, as he had hidden cameras during the rapes. Furthermore, he continued to harass Eden via phone calls. He also kidnapped Julia Wainwright and assaulted Eden's sister Kelly and mother Sophia. When Eden's father, C.C., set up a costume party to help catch the rapist, Andrea Bedford was raped and killed. Several men were suspected of being the rapist, including Cain Garver, Major Hamilton and a bum named Jack. Before Jack could reveal who the real rapist was, he was mysteriously killed. Meanwhile, a pregnant Eden was unsure who her baby's father was: the rapist or her cop husband Cruz Castillo. During this time, Zack became Eden's gynecologist and friend.

Trying to get Zack a girlfriend, Heather set him up on a date with Dr. Diane Bentley, a likable pediatrician. Zack and Diane grew close, but he was revealed to be impotent and couldn't make love to her. Unbeknownst to everyone, Zack turned out to be the Video Rapist! The rapist (Zack) struck again and this time Diane was his victim. That same night, Eden gave birth to a baby named Adriana. A paternity test was run, which Zack tried but fail to steal. Fortunately, Adriana was proven to be Cruz's daughter! Still, Zack managed to get to Adriana and kidnapped her from the hospital, leaving the infant with a French nanny.

Diane became suspicious of Zack, not only because of their failed lovemaking attempt earlier, but also because the smell of soap on his hand reminded her of the rape. She told Cruz about her suspicions. To help Cruz prove that Zack was guilty, ex-hooker Celeste DiNapoli lured Zack to her apartment to find out if he had the same scar on his ankle that the rapist did. When Zack returned to the apartment to attack Celeste, he was caught by Cruz and Michael Donnelly.

Later, it came out that Zack's sister, Claire, was alive but living in a sanitarium. It was also revealed that Zack had been sexually abused by Claire during his childhood, which in turn had motivated his evil deeds. Meanwhile, Cruz chased Zack into the mountains. After one hair-raising confrontation after another, he finally cuffed Zack and together they headed back to Santa Barbara. However, Zack got the jump on Cruz and ran to freedom, only to topple over a cliff! He died, but not before lying to Cruz that Adriana was dead.

Soon after, Ethan Asher became the new D.A. in Santa Barbara. He was the spitting image of Zack, but that was where the similarities ended.