Actually you were all over the map from tax evasion to federal jurisdiction over D.C. The fact still is, even murder is consitutionally a matter of state jurisdiction (when it happens inside a state), not federal jurisdiction.
And no, I'm not talking about when a federal official gets murdered, in case you're going to start playing that angle. That's a different matter.
About murdering federal employees ~ it doesn't have to be done on a federal registration for the federales to get real interested real fast so don't press your luck.