A few things I want to correct:

Let alone the fact he grabbed a man by the neck in the convenience store and stole some swisher sweets
The shooting itself has nothing to do with the convenience store robbery considering the police already told us that the officer who killed Michael Brown had no knowledge of the robbery.

the autopsy report showed he had marijuana in his system
Presence of marijuana doesn't necessarily mean he was high at the time of the robbery or shooting.

His juvenile record said he was charged with murder
His juvenile record hasn't been released, so we can't confirm anything yet.