Show me the "civil rights" double-jeopardy exemption in the US Constitution.
Show me the double standard clause. If it was good enough for the cops vs Rodney King, it’s good enough for a foreign invader who gunned down a US citizen. If they didn’t want the King case to set a precedent, they shouldn’t have done it.
Or are you arguing that foreign invaders who commit murder have more rights than cops who use excessive force?
The reason they use “civil rights” charges in homicide cases is because there is no general federal law against regular old murder. This case is different in that there is a federal crime of being a felon in possession of a firearm. Either way, the concept of double jeopardy does not apply. (Perhaps it should but it does not.)