I wondered if the killer knew him. That area of city is not a sketchy one, and while random violence can happen anywhere it just seemed unlikely, esp given descriptions that he would be unlikely to resist a mugging (and provoke an escalation).
He is not their man yet. Innocent until proven guilty. The word "alleged" is important here. In Journalism 101 they teach you to be very careful when talking about suspected criminals. You don't want to portray someone as guilty until that has been proven in court.
Glad they got their man!