Brazilian authorities are sensitive about their reputation

US Olympic swimmers Gunnar Bentz and Jack Conger have been stopped from leaving Brazil by police examining claims they were robbed in Rio.

Misha Glenny investigated Brazil's criminal underworld for his book, "Nemesis: One Man and the Battle for Rio".

He told BBC Radio 4's The World at One programme how the Federal Police have had some high profile successes against corrupt individuals recently, which has now made them extra sensitive to anybody who appears to be "damaging" the reputation of the criminal justice system.