Scriptonite has the following video well-portraying the influence of racial profiling on people's perceptions of events in her blog piece on the Trayvon Martin case.
In the video, three young actors - one white male, one African American male, and one blonde female - separately go through motions of "trying to steal" the same locked-up yet abandoned bicycle in a local park.
Residents pretty much ignore the shenanigans of the white male and white female, with a few pedestrians making inquiries and even offering to help the young woman in a couple of instances. When the black male youth tries to do the same thing, however, one person after another objects, with an angry crowd starting to gather, some snapping photos for evidence, and one man phones 911, as collective outrage erupts.
(Don't try this yourselves without major planning, back-up, and protection.)
The point being, the pedestrians' perceptions of the exact same incident change drastically with the race and gender of the individual in question. They see the African American male youth as engaging in an objectionable crime, yet the white male and female youths - engaged in the exact same behavior - are seen as doing nothing that out of the ordinary - even understandable in a few instances - since the bike has been left for days.
Of course, in the case of Trayvon Martin, as opposed to this recorded social experiment, Trayvon wasn't doing anything that could be construed as the least bit illegal. He was simply walking home from the store after purchasing some candy and an ice tea.
But he was a young African American male, so he was perceived by George Zimmerman as a "hoodlum" and "thug," although his actions were fully innocent and he was a very nice young person - some have tweeted he was also an honors student.
This is what racial profiling looks like, even among the most ordinary people who don't have any known unusual inclinations towards using guns and violence. So now imagine racial profiling by someone more off-balance than these otherwise good folk (and by even just a little bit) out strolling on a sunny day in the park.
(Now imagine handing that individual a gun.)