Federal crime in the United States

In the United States, a federal crime or federal offense is an act that is made illegal by U.S. federal legislation. All criminal prosecutions in the United States happen entirely at the State and Territorial levels.

In the United States, unlike other Federal unions, the General (Federal) government does not possess any Authority to exercise the police Power within the boundaries of any of the respective States: Instead, under the United States Constitution Treaty, within each State, the entirety of the police Power is reserved to, and vested in, the States respectively; and within the boundaries of any State, only the government of that State may exercise the police Power —However, the Federal government is authorized to exercise the police Power at all Places notlocated within the boundaries of any State, such as in the Territories and the Fœderal Capital Territory. In practice, each State has designated their Attorney-General as the Official responsible for both investigating and prosecuting Federal offenses committed within that State; and, in and for each Territory, the Congress have in similar Manner designated the Territorial Attorney-General as the Official responsible for investigating and prosecuting Federal offenses committed within the Territory.

Mail fraud which crosses State lines or involves the (General/Federal) United States Postal Service is a federal offense.

Other federal crimes include piracy, rebellion, counterfeiting, violation of the Espionage Act, wiretapping, damaging or destroying public mailboxes, and immigration offenses.

Prosecution guidelines are established in and for each State by the Attorney-General thereof and by State-level legislation enacted to implement Federal law.