Edgewater slasher suspect in custody

This past week, a man was going around my neighborhood attacking people at random with a knife. He'd attack them from behind, and then run away. Fortunately, none of the four Edgewater victims was seriously hurt, from what I've heard. The news was rather alarming since Edgewater does not have a very high rate of violent crimes, and random violence like this is rare.

The Chicago Tribune reported today that a suspect was caught following a fifth attack in a different neighborhood. Assuming the police got the right man, we can breathe a sigh of relief that he's off the streets. So why did he do it? From the article:

[Assistant Cook County State's Attorney Heather Weber said that the suspect] attacked the people because they looked at him "weird" or on other occasions the "victims allegedly jumped up and down from across the street."