I guess you would need to know whether it took a few minutes, 15 minutes, half an hour, who knows? The normal police response would be to visit Kinrich's room, search it for evidence, interview his roommate and friends, and so forth. But if it were done in the normal course of an investigation, it would probably take more time than if the whole circle were suspected of being terrorists and were being watched.
I don't know what the timeline was. We have only one student's suspicions to raise these questions. But the news media ought to be doing some investigating, even though they seem to have lost the habit of actually digging up facts.
I agree with what you've said about this. It is curious - I mean even if Cheema had just emerged from the apartment when they grabbed him - how would they know what he looked like - presumably Hinrichs didn't have his pic in his wallet with his name, ya know?
It's all rather interesting...