Former nurse and serial killer Charles Cullen murdered at least 40 hospital patients, including several at St. Luke's campuses. He gave his first television interview this weekend to "60 Minutes." 69 News sat down with a communication expert to analyze what Cullen said -- and didn't say.

If anyone was looking for a mea culpa, they didn't get it.

Steve Kroft, "60 Minutes": "Do you consider yourself a serial killer?"
Cullen: "Uh, I mean, I guess it depends upon a person's definition."

Kroft: "You plead guilty to murder, but you don't use that word."
Cullen: "I think that I had a lot of trouble accepting that word for a long time."

We watched Cullen's interview with Dr. Nichola Gutgold, a Penn State-Lehigh Valley communications professor.

"Very flat. Very, very little emotion," she said. "He doesn't look as though he feels overly sorry for it."

Kroft: "Was it personal?"
Cullen: "No, no."
Kroft: "Did you get pleasure out of it? Satisfaction?"
Cullen: "No. I mean, I, I, I though that, that people weren't suffering anymore."

Gutgold's reaction?

"He says it wasn't personal and that it was just sort of a random thing, and it also even seems to me like he wished he were caught," she said.

Kroft: "Can you give the families anything? Any explanation for how this happened and why this happened?
Cullen: "Like I said, I can't. I just can say, it was more or less, I felt like I needed to do something."

Gutgold said: "He's admitting that he was mentally unstable. He said he needed to do something. Those aren't the words of a rational person."

But for Gutgold, one part of Cullen's interview was particularly telling.

Cullen: "I was caught at St. Barnabus and I was caught at St. Luke's. There's no reason that I should have been a practicing nurse after that."

"He seems to come alive a little more when he's talking about the actions of the hospitals," said Gutgold. "Maybe he's thinking he's caused some good in some twisted way … If I'm so bad, why didn't they put me away a long time ago?"

69 News reached out to St. Luke's for comment on Monday and Tuesday, but have not received a response.