Really? Please cite a statute or a police training manual where a suspect that flees and has been identified by a witness as being involved in a violent crime is presumed innocent.
How do we know that Harris wasn't fleeing because the cop, Deputy Matthew Paul, was trying to rape him in that dark alley?
It's just as plausible as anything you've speculated about Harris. And we do know for a fact that cops like to rape and molest things.
http://www.truecrimereport.com/2009/09/nj_cop_robert_melia_taped_havi.php
http://www.thenewstribune.com/2010/05/27/1202516/officer-allegedly-molested-relative.html
http://www.tcpalm.com/news/2009/jan/22/fort-pierce-police-officer-found-guilty-molesting-/
http://www.lvrj.com/news/former-police-officer-pleads-guilty-in-molestation-case-91547889.html