All crimes are not alike, nor are all criminals.
I grew up during the era of Joel Rifkin, the notorious New York serial killer who brutally murdered 17 women.
It was 25 years ago that Rifkin, then 34 years old, confessed to his crimes after a routine traffic stop in June 1993.
The smell of a decaying body in Rifkin's truck gave the police officers pause. Soon enough, Rifkin told authorities the horrific details: he preyed on women, and would have sex with them before strangling them and dumping their bodies.
Body parts were dumped in waterways, in woods, in oil drums -- even kept at his mother's house. To this day, Rifkin, 59, remains one of New York's most lethal criminals.
Cases like Rifkin's have stuck with me, leaving me to question how such a thing could occur. What makes someone who looks and acts like the rest of us most of the time, suddenly turn into a monster?
That's the question I'm asking in my new HLN Original Series, "Inside Evil," which seeks to expose the nature of the dangerous mind.
Serial killers like Rifkin are a unique breed of perverse amorality: they often don't process and feel like normal people. Their rationales for action often miss basic human considerations, and yet they are able to function without detection in most facets of life.
This duality is at the core of what "Inside Evil" explores -- and it's a dichotomy that forensic psychologists have examined for years.
One question that often comes up when talking about criminality of this level is the nature vs. nurture debate: is it in the criminal's nature to behave this way, or did something happen in their environment to cause this behavior?
From my work on the series, I believe the answer is almost always both. How you're raised or not raised, what life situation stressors you find yourself in -- these are fundamental in the shaping of a person.
However, there are also innate characteristics that can make someone uniquely vulnerable or invulnerable; extreme family traits or circumstances that explain the deviance.
Ultimately, I think nurture can trigger what is in your nature.
In the case of Rifkin -- who, as a serial strangler, employed a uniquely violent way to kill -- he actually doesn't understand why he does what he does. I sat inches away from him, interviewing him to try to get a glimpse into the way his mind works -- and in the end, he didn't know what compelled him to behave this way. When someone doesn't know why they do horrible and deliberate acts -- that's scary.
Because criminals often ignore how their actions affect others, it was important that "Inside Evil" not focus only on perpetrators of violence, but also the survivors.
Through their stories we not only see the wrong that was done, but also true heroism and perseverance that would crush most of us.
The biggest lesson I learned during the making of "Inside Evil" is just because somebody looks and acts like you most of the time, does not mean they are like you.
There is evil in this world -- and it is of our own making. The scariest part is that sometimes people don't even know that someone in their midst, who may even be a friend or a lover or a partner, is a monster.