That's very doubtful. The US shares more submarine technology with the UK (and vice versa) than any other country. Might be the only country in the world I would rule out immediately. Based on the guy's name, Israel seems the most likely, but you never know. Could just be a mercenary deal. Russia, France, China, and Brazil also have a history of poking into submarine work.
Very strange. I hope it's not Israel, but they do have a bad track record for this. On the other hand, as you say, it could be simply a mercenary. Not that that's a comforting thought!