In a dump like Memphis, I would seriously consider the possibility that he fled from them because he didn’t believe they were real police officers.
There was just an incident a few weeks ago that involved people dressed up as Memphis cops robbing people at gunpoint. And that was in a nice area of town.
So yes, if they were plainclothes perhaps Tyree had a reason to run.
Apparently Tyree was just a regular person going about his business. No evidence so far that he had ever been involved in criminal activity.