The question is actually moot, as state crimes cannot be federal violations by virtue of the nature of our Federal system. The Federal government only has those powers which can reasonably implied from the language of the Constitution. The provisions of the Constitution have been construed quite broadly, especially the Commerce Clause of Article I Section 8; however the Federal Government always has been and must remain a government of limited powers.
The states have no such limitation; in fact states hold the police power, the power to effectively legislate to protect and promote the health, welfare, public morals, public safety and morals of its citizens. The Federal Government has no such power. This arrangement is reiterated in the language of the tenth amendment to the Constitution:
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
There is a common misconception that federal crimes are somehow more serious than state crimes. This is not necessarily the case; in fact there are more instances of severe punishment imposed by state offences than federal offenses. Unless the offense charged involves some federal issue, it cannot be a federal offense.