Babak Khorramdin, a 47 year old film-maker, is thought to have been murdered after having an argument with his father over his unmarried status.
His parents, Iran and Akbar Khorramdin, confessed to killing him, admitting that they knocked him out with sleeping pills before suffocating, stabbing, and dismembering him. Three years earlier they had killed their daughter in the same manner, and their son-in-law seven years before that, they confessed during the trial.
The murder was discovered after police were called to the Tehran suburb of Ekbatan after someone spotted human body parts in a bin, according to local media. The film-maker was then identified using his fingerprints, and the police arrested his parents in their house.
The parents claimed that their son-in-law had been abusive, their daughter had been a drug addict and their son had been having relationships with students, said Hussein Rahimi, a Tehran police officer, summarizing the parents' excuses for their actions.
"I don't regret what I did with the cooperation of my wife. They were corrupted and I thank God," Akbar told the reporters during the court hearing.
The incident sparked a nation-wide conversation about the concept of honor killings, and the existence of a legal system that treats parents who murder their children with relative leniency, as the maximum sentence for the crime is only ten years.
The only way in which Khorramdin's parents could be given a maximum life sentence is if they are put on trial for killing their son-in-law, rather than either of their children.
Court officials are looking into whether any other family members have disappeared in mysterious circumstances.