You're finally piecing this together.
Yep, Saint Oz needed to explain why a shoe salesman thought he was ducking the cops.
Turns out the shoe salesman was correct in his suspicions.
So Saint Oz made the very poor decision to throw a punch and pull his gun.
Which resulted in him getting his face caved in and arrested.
Kudos to the alert shoe salesman, Johnny Brewer.
Looking funny isn't a crime. If it was, you'd have been locked up a long time ago.
It's hopeless with these kooks. Oswald was reported by a citizen as acting suspiciously in the vicinity, both in time and place, to a murder. In addition, he has snuck into a movie theatre without buying a ticket (i.e. committed a crime). As a result, the police had reasonable grounds to question him on that basis. Given that they were looking for a murder suspect, they had every reason to approach him as a potentially dangerous individual. He may or may not have turned out to be their suspect but for their own protection they have to proceed with caution which they fortunately did. Oswald's reaction in assaulting a police officer provides ample grounds to take him into custody. Whether that arrest is attributed to assaulting a police officer or murder per se is a pedantic distinction at that point. Oswald's behavior has provided grounds to take him into custody. It also provides grounds to suspect he is their murder suspect. The subsequent investigation confirms he is their murder suspect. Thus, after the fact, it is reasonable to deem the arrest as being for murder even if the arresting officers at that moment would not have been 100% certain Oswald was their guy and were taking him into custody primarily for his assault on a police officer.