As far as I know, there is no statute of limitations for murder in any jurisdiction within the United States. So anyone involved in the Foster murder conspiracy - and who is still alive - can still be prosecuted to this day. What it will take is a degree of political courage that hasn't been seen over the past 23 years.
Interesting you mentioned the District of Columbia in the statute of limitations discussion. DC is the appropriate jurisdiction, because the murder did actually take place there. Note that the official government reports, however, place the death in Virginia.
But it could be that there can be federal criminal charges here as well, perhaps based on Foster's position at the time as a United States official, or perhaps based on the location of the body on federal property.
Please see this post (below) js93. I haven’t had a chance to look at the post yet, but Imgur tends to be predominately liberal because it’s a younger audience, in general. For your possible interest:
http://imgur.com/gallery/cDrseRN
Nevermind, I thought it was all about Vince Foster, but that was just one of the components. Still, for your consideration even though it’s all stuff that’s probably been around for a bit.