The Afflicted (2011)

Hours after his daughter Carla's sixteenth birthday, Hank attempts to run off in the middle of the night, but is caught by his mentally unstable wife, Maggie. The two argue and accuse each other of infidelity, and when Hank threatens to take their four children away from her, Maggie snaps and beats him to death with a baseball bat; after hiding his body, Maggie tells the rest of the family that Hank has absconded with his mistress. Maggie subsequently becomes a shut-in and descends into alcoholism and religious mania, spending most of her time obsessing over Pastor Jon Stackwell, an unscrupulous local televangelist nicknamed the "Cowboy Prophet."

Maggie begins abusing her children, and pulls them out of school when one of them, Cathy, tries to get help from the incredulous Principal Walsh. When they run out of money, Maggie coerces her son Bill into becoming a day laborer, and starts pimping Carla out to a man named Randy. Seeing herself as overweight and hideous, Maggie takes her frustrations over this out on Cathy, and one night forces her to eat canned foods blended with lard; when Cathy stands up to her, Maggie shoots her in the shoulder, and leaves her shackled in the bathtub after making an inept attempt at treating her wound.

When Cathy begs to be released, Maggie agrees to let her go, but only on the condition that she be allowed to remove the bullet from Cathy's shoulder. The "surgery" that Maggie performs on Cathy exacerbates the girl's injury, and she dies from the combination of it and the mixture of vodka and pills that Maggie had given her as an anesthetic. While Maggie is asleep and Bill is out disposing of Cathy's body, Carla tries to run away, and stumbles onto her father's remains. Maggie catches Carla, brings her home, and threatens her other children into bludgeoning their sister with a wooden paddle before locking her in a closet, where she is left to die.

After Carla's death, Maggie pimps her youngest daughter, Grace, out to Randy in her place, and orders Bill to dump and burn Carla's corpse. Carla's charred body is soon discovered by the police, and recognized by Pastor Jon, who races to Maggie's home. Grace, traumatized from being raped by Randy, shoots Maggie to death with her own gun, and then fatally stabs Bill, unaware that he had also been planning on killing Maggie. Pastor Jon arrives at the house, and tries to talk the suicidal Grace down, offering to take the blame for all of the murders, but Grace shoots herself anyway.