42 USC 274e(a) says
It shall be unlawful for any person to knowingly acquire, receive, or
otherwise transfer any human organ for valuable consideration for use
in human transplantation if the transfer affects interstate commerce.
The preceding sentence does not apply with respect to human organ
(3) The term “interstate ...
The US Virgin Islands does have their own criminal code, and the Superior and Supreme courts of the Virgin Islands hear cases related to it (the District Court is a federal district court). However, while I haven't looked at the specific facts in the case against him, I'm sure Mr. Epstein was accused of human trafficking that crossed state and probably ...