The script held in the Crawford Collection in the AFI Research Collection contains the following character notes (excluding regular characters):
'PETER WATSON: The first "natural victim". Aged 25 with a mental age of about 14. Well-built and good-looking, he has a record for sexual offences against young girls. He is picked up as a suspect by the police, and this experience upsets the balance he has struggled hard to attain. He becomes aware that he is losing his battle against his old urges and tries to warn the police, but he is too inarticulate to make his fears clear to them.
'BARBARA O'BRIEN: The second "natural victim". A schoolgirl of 15 or 16 at odds with the world because of a disturbed home background. She senses the dangerous element in Watson's make-up and is attracted to it - "playing with fire." She even has a subconscious knowledge that one day he may kill her, and some compulsion draws her towards this end.
'BRIAN LANE: Age 29-33. About the same build as Watson. A sexual psychopath, but with a non-descript exterior. He seems the average, suburban family man. Fairly smooth and glib. Car driver.
'MR. O'BRIEN: Age 40-45. Barbara's father. He has a business dealing in second-hand furniture. Interested mainly in beer and his greyhounds. Dislikes his wife, indifferent to his daughter. Curses the day he ever got married.
'MRS. O'BRIEN: Age 40-45, but she has let herself go and looks older. The marriage has turned her into a neurotic and nagging shrew. Pretends to care for Barbara but in reality uses her simply as a bone of contention with her husband.
'DENISE WRIGHT: Age 15-16. Attends school with Barbara. A nice, shy, ordinary kid, perhaps even a little young for her age. She becomes Lane's last victim.
'MRS. WRIGHT: Age 35-40. Denise's mother. She becomes worried when Denise goes missing and later has to take the news that she has been raped. A neat, nice sympathetic woman.
'SHOP ASSISTANT (MISS WEST) Age 23 -30. Average looks. Mousy personality. Mr. O'Brien's mistress.
'LESLEY MITCHELL. Age 14-16. Early victim. She has to try to identify her attacker in a line up.
'PROPRIETOR OF CAFE. Age 22-30. Camp and pleasant to all customers. Sympathetic to Mrs. Wright when she comes to the cafe looking for her missing daughter.
'MARY. Age 15-16. Denise's friend, but cheeky and knowing in constrast to Denise's shyness. One scene only.
'YOUTH. Age 18-20. Chats to cafe proprietor. One scene, ordinary all-Australian type.
'PARKIN. Age 29-33. Would help if he had a fleeting resemblance to Brian Lane, because he is wrongly identified as Lane in a line-up.
'TRUCK DRIVER. Any age. Bass singing voice. A big, friendly man who finds Denise after she has been attacked. One scene, driver.
'ANGRY MOTORIST. Age 25-40. Has a minor collision with Lane's car and gets very worked up about it. One scene. Driver.
'HOSPITAL DOCTOR. Age 23-27. Brief scene with Vickers. Dialogue.
'SCHOOLGIRL VICTIM. Age 14-16. Fails to identify anyone at the line-up. No dialogue.
'TEENAGE GIRL. Seen at a distance taking her dog for a walk in the park. One scene. No dialogue.
'FOUR MEN FOR LINE-UP. No dialogue. One scene.'
