The case needs to go to trial. Too much media spin for us to determine what kind of threat she was under when he approached her car, if any.
There is no comparison between the circumstances of this case and the Zimmerman case. Martin did aggressively approach and circle Zimmerman while he was in his car in a threatening manner as Z was talking to the cops, but he did not feel his life was in danger because he was in his car and did not see St. Skittles carrying a weapon.
Had he shot him from inside his car, especially if Martin was unarmed, I would not support that as a case of self defense unless a witness claimed and explained that he had no choice.
Texans don’t generally do moral relativity too well. The grand jury will be looking at the facts concerning the claim of self defense in this case, separate from the Zimmerman case. They are not at all the same.
There are at least two noteworthy similarities...a dead person of a race different from the shooter.I know very little about this case and not much more about the Zimmerman case.As I've said about this case....DNA,fingerprints,ballistics,videos/photos,*reliable* eyewitnesses (meaning no friends or relatives).Lacking those (or,perhaps,in addition to those) look at the history of both.See if one (or both) have a "dirty" past (drugs,booze,criminal record,history of violence,psych history,etc).