As Christiana investigates Il Mostro, she begins receiving strange telephone calls and finds herself being shadowed by a stalker, who at one point attempts to break into her apartment while she is home alone.

After a couple whom she knew personally is murdered by Il Mostro, Christiana attends a séance in the hope that it can summon the victims' spirits, and shed light on the killer's identity; she drops Alex off at a theatre showing a Hitchcock film along the way.

Now paranoid and convinced that Alex is the killer, Christiana leaves the séance and rushes back to the theatre; she is relieved to find him there, quietly watching the movie with the other spectators.

The end credits are preceded by a message that the film was made as a warning to young people, and with the hope of assisting the police in apprehending real-life murderers.

The Killer is Still Among Us was deemed "incredibly boring" in a retrospective Italian review, stating that, while the film did have "a few disturbing scenes", they were not enough to save it from the "banal dialogue" and "bad characters" that made it "a one way trip to dullsville".