"I have seen hundreds of cases of domestic violence. This is a unique kind of crime which sort of puts the criminal in the category of a serial killer. This kind of a person would have the mind of a serial killer. Such people have two personalities. They snap at a point and decide to kill. Such people plan the crime. These people see themselves as victims not as perpetrators," Dr Rajat Mitra, criminal psychologist, said when asked what prompts someone to commit such a crime.