Yes, in a civil rights-era case. James Ford Seale was arrested for three murders in 1964, but the charges were dropped. 36 years later, a newspaper reporter determined that the murder took place in a national forest, which gave the U.S. Justice Department jurisdiction. You'll find more details in the middle part of this article:
http://www.nytimes.com/2011/08/05/us/05seale.html
I bet we'll never see it either, but it's been less than three months since KC's acquittal. We don't know if the feds have anything up their sleeve. What a nice surprise if would be if they slapped the cuffs on her.