The nightmare begins in the cinema during spaghtetti western showing.Suddenly a middle-aged man watching climatic showdown is shot dead.The doors are locked and the police is called to investigate.They have suspects among the audience,but no weapon nor motive.One of the members of cinema staff sits on the same place for the dead man.He is shot dead too.The mystery of killings comes across as a truly perplexing...Overlooked Italian giallo with solid acting and highly original plot.The posters of "Deep Red","Four Flies on Grey Velvet","The Bird with the Crystal Plumage" and "The Perfume of the Lady in Black" are a nice touch.In "Circuito Chiuso" cinema is a mysterious and subversive place,which can easily provoke violent and dangerous fantasies.8 out of 10.