Can a person serving a sentence be extradited? Let's say a person serves a 10 year sentence in the U.S., but China wants to get him extradited so he can be tried and then jailed for murder. How does that work according to U.S. law? Does the person have to serve his sentence before he's detained again for extradition?
The essential law is 18 USC 3184, which says that a judge may issue a warrant for the apprehension of an accused person (given certain legal requirements) to be brought to a hearing. Then
If, on such hearing, he deems the evidence sufficient to sustain the charge under the provisions of the proper treaty or convention, or under section 3181(b), he shall certify the same, together with a copy of all the testimony taken before him, to the Secretary of State, that a warrant may issue upon the requisition of the proper authorities of such foreign government, for the surrender of such person, according to the stipulations of the treaty or convention; and he shall issue his warrant for the commitment of the person so charged to the proper jail, there to remain until such surrender shall be made.
And then the Sec'y of State decides to surrender the person, or not. Since there is nothing in the law that immunizes prisoners from extradition, a prisoner can be extradited. He cannot be extradited to China, because the US has no extradition treaty with China.