It is certainly possible that the federal government would forego prosecution when the state has already prosecuted the defendant for the same act. Indeed, that is fairly common. The Justice Department has a stated policy on when it will pursue prosecution when the state has already secured a conviction. The core of that policy is the following:
This policy precludes the initiation or continuation of a federal prosecution, following a prior state or federal prosecution based on substantially the same act(s) or transaction(s) unless three substantive prerequisites are satisfied: first, the matter must involve a substantial federal interest; second, the prior prosecution must have left that interest demonstrably unvindicated; and third, applying the same test that is applicable to all federal prosecutions, the government must believe that the defendant's conduct constitutes a federal offense, and that the admissible evidence probably will be sufficient to obtain and sustain a conviction by an unbiased trier of fact. In addition, there is a procedural prerequisite to be satisfied, that is, the prosecution must be approved by the appropriate Assistant Attorney General.
Satisfaction of the three substantive prerequisites does not mean that a proposed prosecution must be approved or brought. The traditional elements of federal prosecutorial discretion continue to apply. See Principles of Federal Prosecution, USAM 9-27.110.
In order to insure the most efficient use of law enforcement resources, whenever a matter involves overlapping federal and state jurisdiction, federal prosecutors should, as soon as possible, consult with their state counterparts to determine the most appropriate single forum in which to proceed to satisfy the substantial federal and state interests involved, and, if possible, to resolve all criminal liability for the acts in question.
USAM 9-2.031.
So, the basic process would be that the federal and state prosecutors would usually confer to decide in which forum the case should be brought — federal court or state court. In most cases, the case will only be brought in one of them and not both. For the feds to proceed after the state has already secured a conviction, the prosecutor needs to satisfy the three elements outlined in the policy above and secure the approval of an assistant attorney general (which is a high ranking official of the Justice Department).
Bottom line is that it is indeed possible that the case would proceed only in the Virginia courts and as this is your story you could certainly have it play out that way.