Lately, my attention has been caught on the news of numerous cases of horrendous crimes.
For instance, a middle age man was convicted after he had allegedly attacked his former girlfriend in the kitchen. He had kicked her in the jaw, repeatedly punched her in the face and threatened to kill her before stabbing her twice in the chest with a pair of scissors.
Fortunately, she survived the attack.
Last month, police announced that his sentence had expired and he will be released. He had committed a number of offences, while on remand and refused to take part in a court-ordered rehabilitation programme. His criminal history includes convictions for rape, sexual assault, illicit drugs, domestic violence and grievous bodily harm.
This profile matches a person with antisocial personality disorder. Persons answering that description do not follow society’s norms: they are deceitful and intimidating in relationships, and they do not respect the rights of others. They often partake in criminal activity, and if they do, they are not sorry for their hurtful deeds.
They can be impulsive, reckless and sometimes violent. This disorder is far more common and more apparent in men than women.
They do not “play by the rules” — they do so only if they are threatened with punishment. This attitude leads to a tendency to exploit others. They take advantage of the fairness or softheartedness of others, and they feel indifferent toward or even contemptuous of their victims.
A person with this disorder has little, if any, ability to be intimate with another person. Any lasting relationships are likely to involve some degree of abuse or neglect. Yet, a person with antisocial disorder can be also charming and can be good actors.
They lie and distort reality to keep relationships going. Some with antisocial personality disorder have no goal beyond the pleasure of deceiving or harming others.
While criminal behavior is central to the definition of antisocial personality disorder, this is often the culmination of previous and long-standing difficulties. Clearly, therefore, there is more to antisocial personality disorder than criminal behavior, otherwise all of those convicted of a criminal offence would meet criteria for antisocial personality disorder.
A criminal history is common in this personality. The prevalence of antisocial personality disorder among prisoners is just below 50% (Fazel & Danesh, 2002; Hart & Hare, 1989; Singleton et al., 1998).
This may help you understand these unthinkable crimes.

References
http://www.drugs.com/health-guide/antisocial-personality-disorder.html
http://www.friedgreentomatoes.org/articles/apd_sociopathy_psychopathy.php
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0015230/
http://psychcentral.com/disorders/sx7t.htm
http://darryl-cunningham.blogspot.com.au/2009/11/antisocial-personality-disorder.html