Does this mean that the officer was a racist, and that he fired his gun purely out of hate? Without actually being inside the cops mind, there is no way to know for sure, but we can know for certain that many similar situations have transpired where white officers acted on gut instinct, and not out of animosity towards African Americans.
What needs to be understood by the prosecutors of such cases, and by the public at large, is the distinction between explicit and implicit racism. Where explicit racism is intentional and conscious, implicit racism involves a subconscious bias that causes one to treat members of other races unequally. Implicit racism likely plays a significant role in many of the cases involving white cops shooting black males, and it is also likely that these cops genuinely believe they hold no prejudice at all.
In other words, white police officers may perceive black males to be a threat for behaving in ways that wouldnt seem suspicious for white males.
In fact, an overwhelming number of studies from the fields of neuroscience and psychology provide evidence to support this notion.