It may very well be.
Here's a quote from today's Des Moines Register that should give you pause:
Bob Teig, a spokesman for the U.S. attorney, declined to say why prosecutors dropped the charge. In general, he said, prosecutors sometimes refile charges to account for new developments.…
Amara fled prosecution and has been living openly in Israel since at least June 2008.
So why would prosecutors drop the charge of unlawful flight?
One possible reason may be that Israel is not complying with US requests to arrest Amara.
Another is that prosecutors are gun shy after their debacle with the Law of Return and Rubashkin's bail.
A third reason may be dropping the charge will result in Amara's extradition – either because he has agreed not to fight it if that charge is dropped, or because dropping that charge somehow makes it easier for Israel to extradite.
We may never really know why the charge was dropped, but the fact that it was dropped should give us all pause.