'The Stepfather' includes many suspenseful moments. This is done by using various techniques and theories. Shown in the opening, normality is established at the start. This is done by showing the character's morning routine: Showering, shaving, having coffee and toast and putting the radio on. But this action is subverted by the fact that he is dying his hair and using different coloured eye contacts. By doing this it makes viewers question why he is doing this. It is later answered when the dead bodies of the family are revealed downstairs just before he leaves.
Another one of these methods includes 'False Plateau'. The scene near the beginning shows the suspicious neighbour going outside after hearing the doorbell ringing. Viewers expect the person at the door to be David, the main character and a known killer. However, nobody is at the door, so the woman goes inside with viewers feeling relieved nothing has happened to her. In her house, a sound is made upstairs and the false plateau is repeated when her cat jumps out, both being a thrill and a relief. This does not last long as the killer is only just behind her with his reflection in the mirror and eventually kills her by pushing her down the stairs and choking her.
'The Bomb theory' is used throughout the film. For instance, the character Michael keeps getting closer to catching David in the act, but resists, to the dismay of the viewers anticipating him to go forth. Another example is whenever he chats up a woman (with children and isn't married), we know he is a killer but the characters don't know that, which increases the amount of suspense of the forthcoming events. Overall, it can be suggested that David himself is the 'bomb', as when things get more suspicious, his patience gets shorter, leading to more dramatic results.