Cock Crows at Eleven (1978)

Federico is a child-killer running from the law. Wounded, he is taken in by a 12 year old girl named Simona. Their strange love affair is interrupted by Simona's depressed, oversexed mother Vera, who concocts a plan with Federico to kill her wheelchair-bound, reclusive husband. Simona does not take kindly to this new relationship between Federico and Vera.