A crime was committed and the call went out with a description of the suspects, all units on patrol would have heard it. It’s called a BOLO, it makes no sense that he wouldn’t have known unless he came on duty after the BOLO.
Good point!
When the chief said the officer didn't know Brown had robbed a store, maybe he meant the officer didn't realize Brown himself was the suspect. But the officer would've heard the call.
And if Brown believed he was about to be arrested for the crime, that would explain why he pushed the officer. Seeing how he had no compunction about taking what he wanted and pushing a store owner out of his way, it's not difficult to believe he did the same thing to a police officer if he thought he was about to be arrested.