Howdy Folks!
I believe, unless I am mistaken, that federal criminal charges can still be brought because the man's civil rights (right to life, liberty, pursuit of happiness) were definately taken from him.
http://www.komonews.com/news/local/124815124.html
A jury acquitted Meade of murder and other charges last year, but also determined that the shooting wasn't justified as self-defense. Another officer who was there testified that the shooting was not warranted.
Precedent: After the local judicial system tried officers involved in the Rodney King beating, federal charges were brought and convictions secured!
http://en.wikipedia.org/wiki/Rodney_King
After the riots, the United States Department of Justice reinstated the investigation and obtained an indictment of violations of federal civil rights against the four officers. The federal trial focused more on the evidence as to the training of officers instead of just relying on the videotape of the incident. On March 9 of the 1993 trial, King took the witness stand and described to the jury the events as he remembered them.[27] The jury found Officer Laurence Powell and Sergeant Stacey Koon guilty, and they were subsequently sentenced to 30 months in prison, while Timothy Wind and Theodore Briseno were acquitted of all charges.
Note that King wasn't slain. In this instance, I'd think that federal charges might well apply for violation of the victim's civil rights.
Blessings,
M-Taliesin