The creators and stars of the hit CBS crime drama Person of Interest on Saturday made their third visit to Comic-Con International in San Diego, where they addressed how the once-fictional premise of a machine that can use surveillance cameras, cell phones, the Internet and satellites to spy on people has now become reality.

Created by Jonathan Nolan (The Dark Knight Rises), Person of Interest revolves around ex-CIA agent John Reese (Jim Caviezel) and billionaire genius Harold Finch (Michael Emerson) as they use a computer system — referred to as “the Machine” — that can predict violent acts to secretly try to stop the crimes before they happen.

The panel opened with a video presentation that intercut scenes from the first two seasons with actual footage from CBS News about the controversial PRISM data-mining program the U.S. government is employing to monitor the activities of American citizens.

Nolan and executive producer Greg Plageman were then joined on stage by stars Caviezel, Emerson, Kevin Chapman, Sarah Shahi and Amy Acker for a discussion moderated by SiriusXM Howard 101 Geektime host Ralph Cirella.

Cirella started by asking Nolan what made him decide to create the show — besides paranoia.

“It was all an elaborate scheme to try to get the government to pay us residuals,” Nolan joked before answering, “I was interested in surveillance, and interested in what happens to all that information. What if you had access to it and were in the position to do something with it?”

Cirella noted that people today likely volunteer more information about themselves than the top minds at the CIA could have collected about them 20 ago.

“I read an article the other day that said Mark Zuckerberg is now the head of the largest spying agency in the world, and I think there's something to that,” Nolan said.

“And now we find out that the Machine really does exist,” Cirella said.

“Although our machine is probably a lot more efficient than PRISM,” Nolan corrected.

He and Plageman used the panel to announce that Acker and Shahi have been promoted to series regulars for the upcoming third season.

Cirella asked Acker about her character, the hacker and contract killer Root, and said that while a lot of people think she's mean, he thinks she's just having fun.

“Every time I read a script I get excited and go 'Oooh! I get to say that?' But I don't think she's mean,” Acker said. “I just think that if people don't do what she tells them to, she gets upset. I think we can all identify with that.”

Shahi was asked what will happen with her character, the government assassin Samantha Show, now that she’s left the Office of Special Counsel. Shahi said one of the great things about Shaw is her unpredictability and how she’s like a man with no country. However, she may have a new purpose now that Reese and Finch have brought her in and given her some duties.

“I just gotta say, it's so much fun killing people,” Shahi said. “She's so badass. I get to shoot people everywhere. My husband asks me how was work today, and I say, 'It was awesome. I got to chase boys all day long and then I shot them!'”

Emerson said it was nice for his character to get out of the library last season. He expects more of that this year, although he cautions, “Be careful what you wish for, because then I may end up on a broiling street corner someplace in a three-piece wool suit thinking 'God, the library is a nice set.'”

Cirella opened up the discussion to questions from the audience. The first person wanted to know if the panelists were bothered that Person of Interest hasn’t been embraced as a genre show by sci-fi fans.

.

“I'm unabashed that this is a science-fiction show,” Nolan replied. “I'm a huge genre fan. I don't think I could ever work on a show that couldn't come here to Comic-Con and be celebrated here. I think part of the reason the science-fiction community may not have embraced it is because they sensed that it was actually true. We do like the science-fiction aspect of the show, the cyber-punk aspect of it. Now that reality has caught up with us, our aim for the third season is to push it out a little bit further into that space.”

An audience member asked whether Paige Turco will return this season as professional fixer Zoe Morgan. “Oh, yes. Zoe is the fixer, and shit needs to get fixed,” Plageman said. “She'll be back in a big way.” Nolan said they’re also working to bring back Enrico Colantoni as nascent crime boss Elias.

Another audience member asked if, in addition to the sci-fi elements of Person of Interest, there would also be an exploration of the philosophical aspects, such as whether the Machine is being handicapped by Finch, and what it means to be free.

“I'm with you,” Emerson replied. “To me, the most poignant thing ever on the show is that idea of the Machine being somehow sentient. Independent. Pitiable. Orphaned. I thought what a great notion that is — that we have our heartstrings tugged at by the plight of a disconnected artificial intelligence. I thought that was a great stroke.”

Nolan jumped in: “I remember early on in the development of the show, I was told at some point that in order to get a show on television you had to hide what the show was actually about. You had to pretend it was about something else. So I was sort of going down that path. So then I got a couple meetings in ... and someone asked, ‘What is this show really about?’ I took a chance and I said, 'It's about artificial intelligence and how we are going to interact with it, and the way it will slip into the world unnoticed. It won't land with a giant thud, it will creep in in ways we didn't anticipate. By the time you realize it's here, it will already have meshed into the fabric of our society and we'll barely recognize it — we'll barely recognize what's happening.' I was fascinated by that question, and luckily, it seems that the audience was, too. We very much want to continue in that direction and asking those questions as a philosophical component of the show.”

Nolan closed by mentioning that in celebration of the series finally being able to be viewed online, they’re planning something special and urged everyone to keep an eye on the official Person of Interest Facebook page.

Person of Interest returns to CBS this fall with a new night and time: Tuesdays at 10 p.m. ET/PT, beginning Sept. 24.