Realist said:
Can you explain how the (potential) charges relate to Los Angeles or California as opposed to anywhere else in the USA? How do you decide in which district to bring charges for federal matters that cross state and/or national boundaries? What is the relevant test for where it is appropriate to bring these matters?
the forum was chosen most likely for it having been the jurisdiction which has in personam jurisdiction over the majority of the defendants, coupled with it being the location of the chief prosecutor.
the relevant test is where the majority of defendants are located, such that they are subject to a court's authority. federal courts for the most part have the same geographical jurisdictions (authority) as the state courts of the states in which they sit.
a court's authority over a defendant is achieved by his being physically present within that court's jurisdiction (even temporarily, so long as it is long enough for him to be served with process or arrested--even if just changing planes in an airport), or by maintaining sufficient contacts with, and ties to, the jurisdiction such that being subject to law suits within it is not deemed unjust, unreasonable, or unduly burdensome for him.
for criminal cases in which a defendant is outside of the court's jurisdiction, the defendant would either need to voluntarily surrender himself, or be extradited by the jurisdiction in which he is located. within the US, federal marshals have the authority to arrest and transport federal criminal defendants across state and international borders to stand trial. for defendants outside of the US, interpol and the various national police departments around the world have the same authority, depending on the relevant extradition treaties.
theoretically, federal courts could demand that all US citizens located anywhere in the world defend federal suits in any federal court within the the US, but this is not what was adopted, instead the federal courts abide by the state courts' geographical jurisdictional limitations (with some exceptions).
the subject matter jurisdiction for a federal prosecutor applying federal law, [NO SPECULATION - EDITED BY MOD] is not geographically limited. in other words, any federal district court is competent to hear the case (as long as it has in personam jurisdiction over the defendant).
it is unlikely that the potential charges in the armstrong case specifically relate to violations of any California state laws (and there is no "Los Angeles law," unless you mean its municipal ordinances, which are very, very unlikely to play any role in this case what so ever).
however, choice of law rules allow courts in one jurisdiction to apply another jurisdiction's laws. this happens all the time, all over the world. one case can involve the application of laws from several jurisdictions. so for instance, in this case, the court could apply applicable US federal statutes, US state laws from any of the 50 states, relevant foreign laws from any country in the world, and any relevant international laws that apply via treaty and convention. the test for whether they apply is whether the defendant made himself subject to them, and then violated them. normally, however, only civil laws will be applied this way. it would be unusual for one jurisdiction to apply another jurisdiction's criminal laws.
with racketeering cases it does happen, however, in order to establish that a criminal enterprise occurred. for instance, while a particular offense might not be illegal in the US, if it is illegal in the country in which the defendant perpetrated it, the foreign law might be used to establish that an international criminal conspiracy existed by showing that the foreign law was violated and that the conspiracy was established, at least in part, to specifically to violate it; along with the fact that the ill-gotten gains from violating it were enjoyed in this country. ultimately, it would still be up to the foreign country to prosecute the defendant itself for the violation of its law.
regarding the distinction between circumstantial and direct evidence, instead of thinking of the format of the evidence (testimonial or physical), the best rule is the real rule--whether it requires the trier of fact to infer the conclusion or whether the conclusion is self evident.
this is why most, but not all physical evidence is circumstantial--knives covered in victims' blood and defendants' fingerprints are highly persuasive, but circumstantial nonetheless because the trier of fact must still infer that the fingerprints and blood got on to the knife because the defendant used it to stab the victim.
on the other hand, testimony from a confessed liar, with a proven bias against the defendant, about seeing him stab the victim to death with a knife, is somewhat less persuasive but direct nonetheless, because the trier of fact does not have to infer anything. it just has to decide if the evidence is credible or not.
the combination of the two pieces of evidence, goes a long way toward mitigating witness credibility problems and establishing a reliable inference that the defendant killed the victim with the blood covered knife.
i hope this helps.
my bona fides: graduated from law school in 2003. am admitted to practice in NY, DC, and FL. worked from 2003-2008 in the fraud division of a boutique firm that worked exclusively for lehman brothers. spent 8 months from sept 2009 to april 2010 living and working in the Hague as contract counsel on a very large international commercial fraud case. ich sprech hein nederlands.