Transcript for Rebecca Schaeffer's stalker snaps after her new role in movie: Part 4
Thank you, quiet. And action. One of the things that if you're Rebecca Schaeffer, you're thinking about is, "How can I do a role that's a little different from how people know me?" That's what you're supposed to do in your career. And she gets a big part in a movie called "Scenes from the class struggle" in Beverly hills. My idea of taking a risk is losing my birth control pills or shopping at Saks without a sale. And which has a love scene in it. You need to get a girlfriend before you turn into a pervert. Which is a break from her character that she had played on "My sister Sam." And this flicked some sort of evil switch inside Robert John Bardo. That's what happens in the mind of stalkers. They sit on their sofa. They watch television. And the person's character speaks to them. And then at some point, they get off their sofa. And they go to the door. And here's where you need to hit the pause bottom. Because you can't tell the story -- fully tell the story of Rebecca Schaeffer without first telling the story of Theresa Saldana, another actress who lived in the same west Hollywood neighborhood years before. Theresa Saldana was an extraordinary actor. Her big break came with scorsese in "Raging bull" playing Joe pesci's wife. Change that diaper. Can't you see? Look, she's crying. She stinks. You got a great role. You're in a scorsese film. And isn't this wonderful? And then the horror of your life happens. Actress Teresa Saldana who appeared in the movie "Raging bull" was brutally attacked and almost killed outside her Los Angeles home. This was back in the '80s before there were any stalking laws whatsoever. And there was a drifter from Scotland, Arthur Jackson. I was attacked. A man saw me in a film called "Defiance" which I starred in opposite Jan Michael Vincent. And in his mind, "Oh, she's going to be mine." I have to get to work. He felt that god had ordained them to be together. While Arthur Richard Jackson was deranged, he was also cunning. And so Jackson set out to find a way to get to Theresa Saldana. He hired a private investigator to try to find out where she lived. What this private investigator was able to give Jackson was the unlisted phone number of Saldana's mother. And so Jackson called Saldana's mother pretending to be martin scorsese's assistant and saying that he had a package, perhaps a script, that needed to be delivered to Theresa Saldana. What was her address? And so unknowingly, Theresa Saldana's mother gave Arthur Richard Jackson her daughter's address. He showed up. But he didn't show up with flowers or candy. He showed up with a very sharp knife. And he confronted her and started violently stabbing her. And she played the lead in a dramatization of her own story. One of the unique things about "Victims for victims" is that you have the actress who really experienced the horror event. And she's playing herself. It was unprecedented for Theresa Saldana to be in a movie, to star as herself, as a victim of a knife attack that almost killed her. That's what so unusual. But her motive was to help people, to warn people, to say, "If it can happen to me, it could happen to you." On March 15th, I was delivering water when I heard a female screaming. And I could see a crowd gathering in the middle of Hayworth avenue. I don't know how many times she was sliced by this guy. But multiple people watching everywhere, nobody doing anything. Quite frankly it pissed me off. I grabbed him from behind, not knowing he had a knife, until he pulled the knife out of her chest. Then he turned it on me. At that point, it was a point of no return. I had to fight with him, took the knife away from him. It's hard to describe. I was just doing the right thing. I think her quote was, "I saw a blonde angel." I guess that was me unless there was some angel behind me that I didn't see. It was an absolute miracle that Theresa Saldana survived the attack. Theresa never blamed her mother. It was very important for Theresa to try to absolve her mother from any blame. The mother surely felt blame. Any guilt. But again, the way the story was presented to the mom, she thought she was doing Theresa a favor. She thought that she was helping Theresa's career. She's gonna get her in touch with this big-time director who's gonna give her the role of a lifetime. And she wound up continuing to succeed as an actor. She was an example of someone who the worst thing in the world happened to, gathered her strength and worked not only on behalf of herself but on behalf of others in the same situation. Arthur Jackson served 15 years in prison and eventually died in the psych ward in 2004. But his blueprint for deception would live on and inspire Robert Bardo to use the very same plan. Yeah, the Teresa Saldana case I read about that in "People" magazine. And that's where I got the idea to hire the private investigator. There is this tendency, by the way, for the stalkers to copy one another, study one another. So he hired a private investigator who went to the DMV and obtained Rebecca Schaeffer's home address. It was very, very simple. In his diary, Bardo wrote -- I have an obsession with the unattainable. And I need to destroy that which I cannot obtain. He got himself a greyhound bus ride all the way up from Tucson, Arizona, where he lived, to Los Angeles. And then found himself outside of Rebecca Schaeffer's sweetzer avenue apartment on the morning of July 18th, 1989. He said he just wanted to meet her, but his intentions were much worse than that.
This transcript has been automatically generated and may not be 100% accurate.