This was decades ago, but my friends were robbed in much the same way, in Rio. Most of the street punks that rob foreigners will take anything of value, all your cash, and give back the wallet, credit cards, and passport.
I've been reading in comment sections, on this story, of this happening to other American tourists in Brazil. Sounds like a corrupt police and judicial system in Brazil.
I'm glad Lochte was able to make it out before he got railroaded by their corrupt system. I hope the other swimmers got out of there before that happens to them too.
CGato