From Norman Bates to, well, Norman Bates, it seems every medium has taken a stab at the psycho killer plot device.

Still, a show that gets into the mind of a serial killer each week — examining the high body count and mysterious origin stories — is perfect fodder for television tropes.

“The biggest audiences for these types of shows are females,” says Jim Clemente, a former Supervisory Special Agent at the FBI’s Behavioral Analysis Unit who has consulted on shows like “Criminal Minds,” “The Following” and “Those Who Kill.” “I think women have a basic protective instinct, the same primitive part of our brain that causes us to rubberneck at accidents. Our brain is trying to keep us safe because we want to learn what’s happening and prevent it from happening to us — the risk, the danger, the allure of the really, really complicated killer all make for a more palatable story. These are deep, dark foreboding topic matters being explored with a silver lining at the end.”

Unlike so many real-life killings that are no doubt heart-wrenching for the families involved but would, sadly, typically fall flat in the Nielsen ratings, these on-screen murders revolve around cases with deep intrigue and people with an elaborate, sinister storyline. Some might even liken them to dark romances or trysts, where the audience is teased with red herrings and meant to be drawn back for more until the final scene. Bryan Fuller, showrunner and developer of NBC’s “Hannibal,” equates this to our enthusiasm for Discovery Channel’s Shark Week.

“We are sparrows, they are hawks,” he says, adding that he addresses this fascination through the friendship between Hannibal Lecter (Mads Mikkelsen) and criminal profiler Will Graham (Hugh Dancy). “There’s an aspect of Will that he shares with the audience in that he’s fascinated with serial killers. We’re able to be seduced by the predator in that way that we see the character being seduced. I want people to be confused about how they feel about Hannibal Lecter. There’s that fun yin and yang in the attraction to somebody like that.”

Research into what exactly makes up serial killers (and how common they actually are) continues to evolve thanks to the help of modern psychology, technology and crime scene analysis that allow police departments to quickly share information. This could create challenges for TV shows centered around these premises.

Fuller says his show exists in a “heightened state of reality” and considers his lead “essentially an alien” because “Hannibal doesn’t believe in the rules of society in that they apply to him” and that Mikkelsen plays him as “Lucifer, the fallen angel.”

Scott Buck, executive producer and showrunner of Showtime’s recently departed drama “Dexter,” and his writing staff also considered these developments, while admitting that the show’s darkly demented hero, played by Michael C. Hall, didn’t fit the mold either.

“Over the eight years we worked on ‘Dexter,’ it kept changing what it means to be a psychopath,” says Buck, who says his staff worked with CSI and police experts to get the details right. “Dexter is not a typical serial killer by any means. I don’t think there’s anyone remotely like Dexter. It’s definitely helpful to know what a real psycho killer is … the BTK killer was discovered about that time. He turned out to be an average guy.”

(“Dexter” did feature its own version of a BTK killer in its fourth season. Played by John Lithgow, the Trinity Killer had the outward appearance of a religious father figure.)

The developing research also helps define what we know about behavioral traits of young people with certain red-flag-worthy characteristics. Kerry Ehrin, executive producer and showrunner of A&E’s “Bates Motel,” wrestled with this dilemma when developing the backstory for perhaps the most famous killer in pop culture, portrayed in this version in all his high school angst-ridden glory by Freddie Highmore.

“Norman Bates is different in that he was formed more by his life,” she says, explaining that “the specific disorder with Norman is dissociative identity disorder. It’s basically a disorder that can be brought on by repeated sexual abuse in childhood or repeated violence where the child was in an environment that was so consistently terrifying to him that he literally retreated into himself and created other people to handle things for him.”

While the magic of Hollywood can indulge some fantasies of the way serial killer cases are worked and what these people are capable of, Clemente stresses that the most glaring error is a resolution in 43 minutes. He notes the FBI had about “25 serial killer cases open in a given day” and says that the Charles Manson-like cult that first builds with the help of a prison computer system for Fox’s “The Following” would be hard to replicate in real life because “charisma has to be transmitted in person, not over the Internet.”

Still, a serial killer’s backstory and its long-running effect on society remain a compelling draw for audiences.

“It gives you immediate and very high stakes,” says Ehrin. “That’s important in episodic television. It’s focusing on (the killer) as a human being and it tries to explain where he’s coming from. It’s an unfathomable idea to most people to want to harm anybody, let alone want to kill them.”