Man attacked, apparently at random, with hammer

Did ya'll see this video of a man being beaten with a hammer on a Philadelphia subway? Apparently the victim and perpetrator did not know one another. The victim was asleep on the train prior to the attack. And the perpetrator's son was with him.

A little confusing to me at the end of the video, but not particularly relevant, is that the attacker gets off the train without his one and son's book bag at the end of the clip.

Here's the full "Today Show" story. The attacker was identified by friends/family after the video was shown on local news. He was apprehended at a mental hospital. He has a criminal history. Not sure about his mental health history, but this incident makes you wonder.