But you made it a blanket statement and said; "The witness reports say that Mrtin was trying to get away!"
While ignoring that the witness's reports that Trayvon was on top of Zimmerman, a man calling for help, at one point in time.
That is not, in any sense of the words, "retreating ala running away".
That is what was being pointed out to you, and apparently what flew over your head.
Yes there is direct evidence that Trayvon assaulted Zimmerman.
Zimmerman's statement is evidence.
It is direct evidence.
It is evidence that is not contradicted, and is supported by the physical wounds.
Chasing is an inaccurate characterization.
Following is accurate.
Following someone to keep them under observation until police arrive is not behavior that is wrong.