The problem is that embassies usually are protected spaces where the host country police cannot intervene, the embassy personnel is under diplomatic immunity and the "worst" punishment the host country can deliver is declaring the offender a "persona non grata", but this is a diplomatic affront of the highest severity itself.

No one risks international relationships for a child or a woman.

edit, as I see some downvoting: that last sentence was not meant like I'd support that system. It's just a description how the world works.

I think you are being downvoted because the parent comment was about the situation in the US, and asking if the FBI ignores it.

Your comment about embassies doesn't make a lot of sense in that context.

There was such a case with an Indian woman who was a diplomat, actually. It didn't go over well, politically.

http://world.time.com/2013/12/17/indian-diplomats-arrest-in-...

The question was about forced polygamy groups, not South Africa.

it's difficult to get the FBI involved. They tend to take on only the most extreme cases.