They knew it was Hinrichs shortly after he blew up, because they found his wallet. They naturally are looking for his Islamic roommate. They grab the roommate as soon as he exits the apartment
Now, here's the thing I'm curious about: how is it the cops were waiting right outside the apartment for Cheema to come out? It suggests they had the apartment under surveillence. How long was it under surveillance, and what caused the cops to decide to put it under surveillance?
Inquiring minds would like to know
That was my thought, too. I can understand how they id'ed Hinrichs, but usually it takes awhile to go through friends or records to find out (a) there is a roommate, and (b) what his name is.
But maybe the authorities suspected he would commit suicide in a dramatic fashion. (Yes, that's sarcasm, in case anyone wonders.)
I wondered that, too, but it *is* the same apartment complex, so maybe someone else there told Norman cops they had seen Cheema go 'over there.' Barakat did say that Cheema went to that apartment all the time, so it's a regular occurrence.
I do feel sorry for Cheema, as being hard-of-hearing, cuz I can imagine how the officers yelled at him. *If* he's innocent, that had to be upsetting.
I think I remember that Cheema was scheduled to leave for Algiers soon.