Ironically, part of the issue here is the targeted sanctions approach that the US and EU adopted for pressuring Zimbabwe:
U.S. sanctions do not block the Government of Zimbabwe as a whole, nor do they prohibit all business with the country of Zimbabwe or transactions involving that jurisdiction.
So the hedge fund manager invests in CAMEC. CAMEC's principals are eventually put on the sanction list, but only well after the investment.
BTW, the EU is in the process of abandoning its sanctions on Zimbabwe. The US not so much, but the targeted nature means they were of extremely limited effectiveness anyway.
For being a such crazy MF, Mugabe really did a good job of flipping off the entire world and getting away with it.