How is suspense created in the stepfather?

Throughout the 'The Stepfather' suspense is created to show the characters mind frame. the main character is seen as a twisted, demented human being as he murders for no good reason. We see this when he kills a harmless old women and the father of his soon to be step children. suspense is used by using a false plateau when we see the cat jump out on the old women when we are expecting the villan David to turn up, as the audience we are relieved to see the cat jump out. As she carried on walking David shockingly appears out of one of the doors and violently brings her life to a tragic end by suffocating her with no remorse.