Andrew Urdiales is a confessed serial killer who hunted and killed eight women in cold blood in California and Illinois. Chris Cuomo interviewed him for the HLN documentary series "Inside Evil."

Editor’s Note: Chris Cuomo anchors CNN’s “Cuomo Prime Time,” a 9 p.m. nightly news program where Cuomo tests power with newsmakers and politicians from both sides of the aisle, and reports on the latest breaking news from Washington and around the world. Jessica Velmans is an HLN Original Series executive producer. The opinions expressed in this commentary are those of the authors; view more opinion articles on CNN.

CNN  — 

As I traveled to prisons around the country for the third season of my HLN documentary crime series, “Inside Evil,” one thing stood out to me: the series’ title really seemed to get under the skin of the convicts whom I interviewed.

These inmates have cut short the lives of siblings, women and friends in calculated and gruesome ways. John J. Lennon, for example, shot a former friend at close range with a weapon that could “take down a small army,” according to former Brooklyn ADA Stephen Murphy. Missouri inmate Lisa Harris was seventeen when she brutally beat and stabbed a man to death with a group of friends in the Ozarks. Paris Lee Bennett stabbed his four-year-old half-sister Ella seventeen times.

And Andrew Urdiales is a confessed serial killer who hunted and killed eight women in cold blood in California and Illinois. He was called “the living embodiment of evil” by Orange County DA Matt Murphy.

But I still took a lot of heat for referring to them as “evil.” As this gripe came up over and over again, I began to wonder why this word – which is defined as “profound immorality and wickedness, especially in people’s actions” – would bother someone who admits to having committed the atrocious act of taking the life of an innocent victim.

It’s a question that takes a stab right at the heart of the topic I set out to explore in the series: the psychology of extreme violence.

Psychopaths have brains that are fundamentally different from the average person’s, according to Dr. Abigail Marsh, a neuroscientist at Georgetown University. Their amygdalas, a region of the brain, respond less to signs of another person’s fear and whether it would be acceptable to intimidate them, she says.

Forensic psychiatrist Dr. Park Dietz, who has analyzed many of our country’s most notorious criminals, told us serial killer Urdiales described murdering women as a way of relieving pent-up tension. “He is motivated by revenge against the world, especially women, women who rejected him, women who didn’t provide for him.”

Urdiales started killing in 1986 when he attacked Robbin Brandley, a twenty-three-year-old student on the campus of Saddleback College in California. As she was walking to her car, he jumped out of the bushes and brutally stabbed her forty-one times. His killing spree went on until he was apprehended in Illinois in 1997. In total, he was charged with eight homicides. Only one woman, Jennifer Asbenson, managed to get away when Urdiales abducted her and forced her into the trunk of his car in the desert near Palm Springs. “I knew he had no sympathy, no empathy, no compassion,” she said. “All I saw was hate.”

Yet when I met the shackled Urdiales, the first thing he said to me was: “I just have some concerns about how I’m going to be portrayed. I know your show is called ‘Inside Evil.’”

For the record, I answered, “It concerns me too because of the kinds of people I wind up meeting while we’re doing these documentaries.”

When I asked Lisa Harris if she thinks of herself as a murderer, she responded, “It is not who I am. It is what I was involved in,” eschewing the label that led to a life sentence. John J. Lennon, too, believes “you’re not your worst deed.”

Urdiales, who cut short the lives of so many young women, would not answer why he has an aversion to being called evil.

Our series invites you to meet the people whose violent acts test the boundaries of humanity, as I try to understand how their dangerous minds work.

The third season of “Inside Evil with Chris Cuomo” premieres Sunday, June 30 at 9 p.m. ET/PT on HLN.