
This episode discusses the Otero family murders in Wichita, Kansas, on January 15, 1974, and the subsequent investigation into the killings.
The episode begins with the arrival of 15-year-old Charlie Otero at his home, where he finds his family missing and the house in disarray. He discovers the bodies of his parents, Joe and Julie Otero, who were brutally murdered, along with his younger siblings, Joey and Josie.
Investigators detail the crime scene, noting the signs of struggle and the methodical nature of the killings. The police face challenges in identifying a suspect, as the community grapples with fear and confusion over the brutal nature of the crime.
As the investigation unfolds, the episode highlights the lack of forensic technology at the time and the extensive efforts made by law enforcement to solve the case, including interviewing over 1,500 individuals and exploring various leads.
The narrative also introduces the BTK killer, who later claims responsibility for the Otero murders through a letter, revealing his disturbing motivations and the psychological profile of a serial killer.
The episode covers the brutal Otero family murders and the ensuing investigation, revealing the emergence of the BTK killer.

This episode stands out for the following:
"Mom and dad are playing a bad trick on us.".Serial Killer Confesses in a Library Book (Part 1/4)
"All murders are unpleasant, but this is one of the worst I've seen.".Serial Killer Confesses in a Library Book (Part 1/4)
Every time we have a theory, something pulls it apart.Serial Killer Confesses in a Library Book (Part 1/4)
The crime had been driven by a psychotic sexual perversion.Serial Killer Confesses in a Library Book (Part 1/4)
This is not going to work.Serial Killer Confesses in a Library Book (Part 1/4)
If my gut instinct is correct, surely was a victim of BTK.Serial Killer Confesses in a Library Book (Part 1/4)