"Federal de narcóticos (Division Cobra)" also takes the story of "Mil gritos tiene la noche", about a murderer who kills young people on a campus and later an undercover policewoman goes in as a teacher in search of the murderer. The difference is that in "Mil gritos tiene la noche" the murderer mutilated his victims with an electric saw explicitly, in "Federal de narcóticos (División Cobra)" the murderer is a strangler and there are no explicit or bloody deaths.