Odessa, TEXAS (ABC Big 2-FOX 24) – Crime shows, books, and podcasts seem to be everywhere you turn.

“Every week there was a serial killer that we were chasing. There are not that many,” says UTPB Criminology Assistant Professor Dr. John Fisher.

It’s a popular topic, but UTPB Associate Professor Doctor John Fisher says it’s an exaggerated one.

“The FBI says there are probably about 35 serial killer running active across the country at any given time,” says Dr. Fisher.

Every case can be different, but experts have learned a lot about serial killers, like what kind of person they tend to be.

“A common profiler for a serial killer is a while male who starts killing in his 20s, ends killing in his 30s or 40s. Normally a high IQ or a higher than average IQ, slightly balding,” says Dr. Fisher.

Experts have also learned what their motivations could be to take the lives of others.

“Lust. Desires. It’s much like drugs, and/or any other activity that you like doing. It fires off the endorphins, it makes you feel good, and you’ll want to feel that again, and you want to continue to feel that way. Most of your serial killers, or a lot of your serial killers- it’s a progression crime. They’re going to start with stalking, voyeurism, peeping Tom. Then they’ll go to breaking in, rape, and then murder. There is no real one-size-fits-all for serial killers,” says Dr. Fisher.

It’s a concept people typically don’t understand, but they want to understand. It’s so interesting to some that Dr. Fisher teaches a class on profiling.

“When I talk to my students and I ask them, ‘Why did you take this class?’ They all answer, ‘I don’t understand why somebody could be a serial killer. I want to understand why.’ Then we spend weeks profiling, why these different serial killers did the different things that they did,” says Dr. Fisher.

Dr. Fisher says at their core, killers want to find joy.

“That’s one of the things that you’ll find with all serial killers, is that they’re focusing on their happiness and achieving their wants and needs without any concern of the victims,” says Dr. Fisher.

He says they’ll do whatever it takes to find that happiness.

“One of the things we do know is that once a serial killer starts killing, he’s not going to stop until he’s dead,” says Fisher.

Which is why studying these crimes, and the people who commit them, is so crucial.

“With the amount of and quality of investigative techniques, DNA and other crime scene technology that we have, we’re catching serial killers a lot faster, and before they’re considered serial killers,” says Dr. Fisher.

According to the FBI, serial murderers are estimated to be less than one percent of all murders committed in a given year.