Transcript for 'Golden State Killer' suspect charged with eight murders: Part 5
He's been called the east side rapist, the original night stalker, the golden state killer. Today, it's our pleasure to call him defendant. Reporter: It was the first of likely many appearances before a judge last week, as Joseph Deangelo was rolled into a Sacramento courtroom. In custody, Deangelo. Reporter: The 72-year-old appeared sullen and feeble, barely enough energy to respond to judge Michael sweet. Is Joseph J. Deangelo your true and correct legal name? Yes. I'm sorry? Yes. Reporter: Cuffing him to the wheelchair seemed almost pointless, his eyes barely seem able to stay open as the charges were read. I think that he was either tranquilized or it's all an act. It was an act. You don't believe it? I don't believe it at all. Completely faking it. Reporter: You thought it was a big show? Yep. This is a physically capable 72-year-old man. For him to be in that wheelchair, based on what was seen in the week prior, he's fakin' it. Reporter: The week before he was arrested, he was seen riding a motorcycle? Yes. He's the ultimate tactician. And now he is employing a strategy to get sympathy. "I am a frail old man." Reporter: So far Deangelo's been hit with eight murder charges spread over three counties. On this day, two counts for the 1978 double homicide of Katie and Brian maggiore, no bail. And a public defender. He couldn't speak. She had to lean in. I wouldn't touch him. To hear his words. When you hear his neighbors tell you that he could be heard shouting in anger. Come on, dude. Let's make it a fair fight. Let's go. Stand up. Reporter: Frail or not, Deangelo will likely avoid prosecution on the 50 rapes he's suspected of. He raped a housewife. There was a knife used. Reporter: The statute of limitations has long since expired. But there's no statue of limitation on murder. It's a long arm of the law. It took 'em 40 years, but they found him. And now he's gonna pay. Reporter: If convicted he could face the death penalty, but for now, there are unanswered questions about Deangelo's alleged reign of terror. First, could it have been even worse than authorities suspect? I was wondering what else had he done. Who knows? He might have gone to summer camp somewhere. He might have gone on vacation somewhere. Reporter: Still, there is much speculation about one big question, why did the golden state killer finally end his years-long crime spree? Reporter: What do you think happened? In 1981, he ends up going into kill Gregory Sanchez and Cheri Domingo. And he gets in a physical fight with 6'3" Gregory Sanchez. And I think that physical altercation with Sanchez scared him. We don't have an attack for five years. But then he runs across beautiful 19-year-old Janelle Cruz and can't help himself, and kills her. But at this point, he's an aging offender. His testosterone might have gotten lower. He might have gotten heavier. He wasn't able to jump around the way he was doing before. I always felt he quit because he lost the ability maybe to control, maybe to be as agile and as quick as he used to. Reporter: So, he just retired from the killing business? I think it's possible, but it's also possible there's attacks out there that we haven't linked to him. Reporter: Even if the killer finally gave up on rape and murder, criminal profilers Mary Ellen o'toole and ABC news consultant Brad Garrett, say its possible the killer didn't stop in 1986. He just moved on to different crimes or changed his M.O. If you're psychopathic, you're psychopathic and you're gonna take that to your grave. It is just unbelievable to me that he stopped cold Turkey in 1986 because those urges don't go away. Reporter: Perhaps the biggest unknown, is it even possible to know what triggered the rampage. Fantasy drives him, and the fantasies get richer and fulfill whatever excitement, thrill, need, sexual thing he needs, he's gotta bump it up a notch. When people have those facades of normalcy around them, good jobs, good backgrounds, good families, they fly under our radar screen far longer than that serial killer that's out there just grabbing people off the street. Reporter: Just yesterday, Deangelo's public defender was back in court, failing in her attempt to block investigators from collecting more DNA, finger prints, and photographs, of specific parts of Deangelo's body. As for Paul holes, he personally doesn't need anymore evidence. Reporter: Now that you've seen his face after all these years, what do you see in his eyes? I saw glimpses of the evil when he saw a female and his face turned into rage briefly in custody. And I thought, "That is the real Joe Deangelo."
This transcript has been automatically generated and may not be 100% accurate.