Pretty Poison (1968)7.0 /10

Storyline:  After years in a psychiatric hospital, Dennis Pitt is released under supervision but soon disappears to start anew in Winslow, hiding his past. Convinced his company is part of an alien plot to poison the water, he obsessively gathers evidence. When he meets Sue Ann, a teenager eager to escape her repressed life, Dennis convinces her he is a secret agent. Their romance fuels both of their unstable fantasies, steering them toward a devastating outcome.