Lets say that I commit a crime in which the USA and another country both have jurisdiction. As an example I, a US citizen, kill Bob, a citizen of country X, while we're located in Antartica.
Country X catches me first and puts me on trial; they refuse to extradite me to the USA when asked. However, for some reason X has some bizzare rules that makes them far more lenient towards my crime - maybe the leaders X are all horrible racists towards Bob's race, which means it's both more likely that I will be found 'innocent' of the crime despite my having done it and I face a drastically lower penalty if found guilty.
Eventually some time after the trial I return to the USA. The local authorities would like to see me face a harsher penalty for my crime. I'm wondering if they have any way to try or imprison me under these circumstances:
- I was put on trial but found not guilty of the crime
- I was found guilty, spent 2 weeks in jail and paid a 50 dollar fine
- I was found guilty of a crime for my actions, but the crime was different from the crime as the USA would define it (for instance the country is so horribly racist they don't consider killing a member of Bob's race murder and instead tried me on something else like animal cruelty).
Would it matter if the countries have an extradition treaty, or if the crime was something other than murder, like bribery or grand theft?