Pretty Poison (1968)

Synopsis
Easygoing but psychotic Dennis (Anthony Perkins) is released from jail, where he has served a sentence for his complicity in a suspicious death. Wandering through a small, working-class New England town, Dennis befriends apparently normal high school A-student Sue Ann (Tuesday Weld). He fills her head with lies about his imaginary career as a secret agent. She is thrilled, and makes up her mind to join him in his further adventures. This jet-black "who's manipulating who?" seriocomedy was adapted by Lorenzo Semple Jr. from Stephen Geller's novel She Let Him Continue. ~ Hal Erickson, All Movie Guide