The crime drama Mindhunter, now on Netflix, stars Jonathan Groff as Holden Ford, a young hostage negotiator who travels around the country in the late '70s interviewing killers to figure out what makes them tick. His colleagues doubt him, except for Bill Tench (Holt McCallany), a behavioral-science specialist based on another notable early profiler, Robert Ressler.

If Ford's story sounds familiar, there's a good reason. The David Fincher drama is based on the book Mind Hunter: Inside The FBI's Elite Serial Crime Unit by John E. Douglas and Mark Olshaker. Douglas is a former FBI Special Agent and one of the country's foremost criminal profilers. Starting in the late '70s, when he was still in his early 30s, he worked for the Bureau's Behavioral Science Unit, teaching hostage negotiation and criminal psychology to FBI agents and police officers.

Jonathan Groff, MindhunterJonathan Groff, Mindhunter

As he traveled around the country teaching, he would interview serial killers and sex offenders in prison to get a better understanding of what made them tick. At first his colleagues doubted and criticized his methods, but they came around when they saw the results. He eventually created and ran the FBI's Criminal Profiling Program and was head of the Investigative Support Unit.

Douglas' influence is clear in Ford, but he's far from the only character directly inspired by the FBI agent. Douglas' books helped criminal profiling become a pop cultural fascination, and he became the model for nearly every notable FBI character you can think of who's tried to think like a serial killer.

Here are all the guises you've seen Douglas in before.

Laurence Fishburne, <em>Hannibal</em>Laurence Fishburne, Hannibal

Jack Crawford
Jack Crawford was created by author Thomas Harris in his novel Red Dragon, which also first introduced Hannibal Lector. The character shared Douglas' leadership position at the Behavioral Science Unit and was based on the FBI agent at a more established point in his career than Mindhunter's young striver. He was first played by Dennis Farina in the movie Manhunter, which was based on Red Dragon. After that, he was portrayed by Scott Glenn in The Silence of the Lambs, which was based on Harris' second Hannibal Lector novel. Crawford was then played by Harvey Keitel in Red Dragon, Anthony Hopkins' third go-round as Hannibal Lector and the second adaptation of the novel. Most recently he was played by Laurence Fishburne on the TV series Hannibal.

Hugh Dancy, <em>Hannibal</em>Hugh Dancy, Hannibal

Will Graham
Will Graham is another Thomas Harris character who's appeared in all of the adaptations, but he's usually not based on anyone in particular. However, in Hannibal, Hugh Dancy's Graham had one notable thing in common with John Douglas: a severe case of viral encephalitis, which Douglas suffered from in 1983. The condition, an acute inflammation of the brain, caused Will to suffer from hallucinations, lost time and disorientation — all things which Hannibal took advantage of while keeping the diagnosis from his patient.

Mandy Patinkin, <em>Criminal Minds</em>Mandy Patinkin, Criminal Minds

Jason Gideon
The first leader of the FBI's Behavioral Analysis Unit on Criminal Minds, Jason Gideon (Mandy Patinkin) was another Crawford-like commanding officer character based on John E. Douglas. Gideon's job title, methods and difficulty separating his personal and professional lives are directly drawn from Douglas. However, even pretending to deal with the troubling issues Douglas dealt with in his real career proved too much for Patinkin, who quit the drama after two seasons claiming the series was "destructive to my soul."

Joe Mantegna, <em>Criminal Minds</em>Joe Mantegna, Criminal Minds

David Rossi
Gideon's replacement, David Rossi (Joe Mantegna), is also inspired by Douglas. Like his friend Gideon, David also has trouble at home due to his work. And like Douglas, he's an author, having published numerous books on serial killers. To blur fact and fiction even further, Douglas and Rossi have both interviewed the same famous serial killers, including Ted Bundy and Charles Manson.

Mindhunter is available to stream on Netflix.