 Kevin Lyon observes , " The plot revolves around the audacious and quite unexpected transference of guilt from the maniacal killer ( about whom we learn very little , itself unusual for Argento ) to the eminently likeable hero , surely the film 's boldest stroke . " While noting that the device is " striking " , McDonagh comments that this guilt transmission / transfer occurs between two dark doubles who are seriously warped individuals . She suggests that " Neal and Berti ... act as mirrors to one another , each twisting the reflection into a warped parody of the other . " Berti 's obsession with Neal 's fiction compels him to commit murder in homage to the writer , while Neal seems to think that his own violent acts are simply part of some kind of " elaborate fiction " . When the bloody Neal is confronted by Giermani immediately after having killed numerous people , Neal screams at him , " It was like a book ... a book ! " 
