Director Nelson McCormick uses many different techniques to create suspense. Three major ones he used was Bomb Theory, False Plato & Normality.
Is established at the start of the film. The Stepfather has showered and shaved but the dying of hair and change of eye colour firstly raises audience awareness. Then he puts on the radio and drinks his coffee, eats his toast however suddenly we see dead bodies. The normality instantly stops for the audience and creates suspense however what creates even more suspense is that normality still exist for The Stepfather.
Throughout the whole film this technique exist. the single mother and children do not know that The Stepfather is a murderer and is planning to murder them. On the other hand the audience do know, this keeps us on the edge of our sits waiting to know if he'll murder them? Will they find out in time? This is called the bomb theory, when the audience knows something the characters do not.
This technique appears many times in the film. Firstly with the old women who's a neighbour to the family, the music and camera angles make it look like The Stepfather is in the house but then it is all calm when we see its just the cat that jumps out, then suddenly when everything was calm The Stepfather strikes and kills the old woman. Also when The Stepfather was supposed 2 be dead and the mother and her son are hugging he returns to finish his job of killing them. This is false Plato, when everything seems to be fine but is not.