Is 'Mindhunter' 's Holden Ford Real? The True Story of FBI Agent John E. Douglas

The serial killers aren't the only characters based on real-life subjects in the hit Netflix series, Mindhunter.

The show's main protagonist, Holden Ford, is loosely based on former FBI special agent John E. Douglas, who was one of the bureau's first criminal profiles. Many of the stories from Mindhunter are taken straight from Douglas' novel, Mindhunter: Inside the FBI's Elite Serial Crime Unit.

So who is Douglas?

Douglas, 74, joined the FBI in 1970 at the age of 25 to work on violent crimes. He was a member of the SWAT team before he became an instructor in hostage negotiations and applied criminal psychology, according to the Powell Tribune.

Much like on the show, Douglas was teaching when had the idea to interview real-life criminals in hopes of better understanding their motives and what led them to kill.

"I conducted the research, not from a rehabilitation perspective, but from an investigative perspective," he told the Powell Tribune. "It was considered innovative, but to me, it was basic. If you want to learn about violent crime, talk to the experts: the criminals perpetrating rapes, arsons and serial homicides."

This led Douglas to create the FBI's Criminal Profiling Program.

"Most of the people we interviewed came from some type of a dysfunctional family," he added.

The first season of Mindhunter saw Ford interview a number of famous serial killers, including Edmund Kemper (Coed Killer), necrophile Jerry Brudos and mass murderer Richard Speck — all of whom Douglas also interviewed in real life.

During his first year on the project, Douglas interviewed 59 serial killers. By 1995, he received more than 1,000 requests for criminal profiles.

He also interviewed David Berkowitz (also known as Son of Sam, who is featured in season 2), Ted Bundy and even Charles Manson.

According to The Guardian, Douglas' interview with Bundy contributed to the arrest of The Green River Killer in Washington.

But one of the serial killers who fascinated and disturbed him the most was Gary Heidnik.

"Heidnik would fill the pit up with water and not drown [his victims] but have them stand in water up to their necks and then get electric wire and torture them while they were in the water," he told Fox News. "He was definitely shocking."

After an undeniably successful career in the FBI, Douglas eventually retired in the '90s, admitting the job took a toll on his personal life.

"It causes stress in the family," Douglas told Vulture earlier this year. "Say your child falls off a bicycle and hurts her arm, you get home and it is a big deal. But you've seen, earlier that day, a young child who was brutally murdered, so you may come across like you're hardened."

Along with writing his book, Douglas has also continued to consult on cases — including the Jon-Benet Ramsey killing.