I predicted it would be Mossad, but mainly because i couldn't think of anyone else it could be. I did fail to notice that the woman was the girlfriend, though, so no points for me.
The final deal seemed pretty cold but it actually makes sense. The soviets can use someone involved in stealth research. And as for Israel, well back then the dominant political party was getting mostly askanzi votes, whereas their closest rival was getting most of the sephardics. And so the israeli government was actually pressuring Washington not to accept jewish russians (who are askanazi) as immigrants so that they would go to Israel instead and help keep the party in power.