Episode 3 is the third episode in the Mindhunter series. It premiered on October 13, 2017.
Dr. Wendy Carr joins Holden and Tench in their first success, when their insights lead to an arrest.
In Park City, Kansas, Dennis stands on a suburban street, staring at a mailbox, before getting back into his van and driving away.
In Boston, Massachusetts, Bill and Holden go to visit Dr. Wendy Carr, a professor, who says that she agrees about what they're doing. How it can be helpful to talk to these criminals. She says that their work could even lead to a book one day. Holden really likes this idea but Bill is against it. Wendy proposes that this could become a full-blown academic study. She says that these men are virtually impossible to study but that they've found a way to do it. She also tells them that this is really important work and that someone needs to do it. Bill tells her that they just don't have the time.
Bill and Holden go to visit another criminal but when they arrive they are told that the criminal doesn't want to speak with them. They return to their office where they try to plan out which criminals they are going to interview. They get a call about a murder that just happened so they head back to California to talk to the cops about the case. They learn that it's a repeat killing and they begin calling the suspect a sequence killer.
They go to talk to a suspect who they believe could be responsible for the killings. The man they approach is still living with his mom, single, and doesn't have a dog. They ask him how he got the scratches on his arm. He is adamant that he got them from a piece of wood. They end up arresting the man who they believe is responsible. They return to the police station where they have a celebratory party.
They pay Kemper another visit and talk to him about his first kills. This time they brought a tape recorder. At the end of the episode, Wendy Carr arrives at Quantico.