Basically, there are two scenarios leading to the filing of a criminal case in federal court: (1) there is an alleged violation of federal, as opposed to state, law; or (2) the crime alleged took place on federal property. Actions which violate both state and federal laws may be prosecuted in either (or both) jurisdictions without violating the constitutional prohibition against double jeopardy.
Acts committed on federal property may violate either state or federal laws as well, although they will always be prosecuted in federal court by virtue of the fact that they occurred on federal property. If an act committed on federal property violates state law only, it will be prosecuted in federal court under the substantive law of the state where it occurred, although federal rules and procedures will apply.
Types of federal crimes
The federal criminal code (set forth mostly in Title 18 of the United States code) contains over 120 categories of crimes, organized by subject matter. Additional federal codes contain other criminal prohibitions. Title 18 also contains the federal rules of criminal procedure, which set forth the rules which govern the handling of criminal cases from start to finish. In border states like California, the most prevalent types of cases are:
controlled substance violations;
immigration law violations;
mail OR wire fraud;
bank larceny OR robbery;
gun laws (such as a felon in possession of a firearm);
postal offenses;
child pornography;
counterfeiting; and
crimes of any type which occur on federal property or in federal buildings.
Criminal laws have been increasingly "federalized." More and more are offenses subject to federal prosecution.


