Leandro killed his Mother and stepfather then cut their bodies and fed it to the family's six dogs. He also said his stepsister Karen Klein assisted him in the act. The two were in an incestous affair for six years.
Leandro and Karen did not express any remorse as they believed the abuse they suffered in the hands of their parents led them into the act.
The two had become very angry when they discovered the dead couple abused their 11-year-old siblings.
According to his lawyer, Leandro said he committed the crime because of the abuse he suffered in the hands of his stepfather.
From inside a special psychiatric unit, Acosta confessed he had been planning the gruesome murders of his step-father Ricardo Klein, 54, and mother Miryam Kowalczuk, 52, for some time.
His mental state had been worn away by the years of abuse he suffered at the hands of Klein, who began raping him aged six, and Kowalczuk, who 'involved him in threesomes' as a boy.