Obsessed also known as Anna Obsessed and Blue Obsessions is a 1977 pornographic film directed by Martin amp Martin, and written by Piastro Cruiso.
In the Carson home, Anna and David discuss their failing marriage before David goes to work, where he makes dinner plans with his secretary. While out shopping one night, Anna is sexually assaulted by the Long Island Rape Murderer. After Maggie invites her over, Anna confides in Maggie about being attacked, and the two enter a relationship, while David begins an affair of his own with his secretary. The Long Island Rape Murderer continues to stalk Anna, steals objects like pictures and underwear from her, and has erotic fantasies about her.Anna has sex with David flashing back to being raped in the midst and afterward tells him about how she believes Maggie can help their floundering relationship. The Long Island Rape Murderer is shown angrily destroying a photograph of Anna, who has dinner with David and Maggie, then a threesome. After the trio finish, Maggie is revealed to be the Long Island Rape Murderer, and she shoots David and Anna. The police arrive, and as they arrest the seemingly catatonic Maggie, she shoots a detective, and is turn brought down in a hail of gunfire by a lieutenant. ........
Source: Wikipedia