Two Cuban boxers who defected during last month's Pan American Games in Rio de Janeiro have been detained by police in a town some 108km (67 miles) away.
Cuban boxers are not allowed to turn professional
Police said they went to pick up Erislandy Lara and Guillermo Rigondeaux, favourites to win gold at the games, after an anonymous tip-off.
They were being held while their situation was resolved, officials said.
Reacting to their defection, Cuban President Fidel Castro had accused the boxers of betraying their country.
The boxers' foreign accents and way of behaving, as well as Erislandy Lara's gold teeth, had attracted attention of residents in the beach area of Praia Seca in Araruama, police said.
Police officials said the boxers had not been arrested, but were being held to await the next steps concerning their stay in the country.
Rigondeaux, 25, who is a double Olympic and amateur world bantamweight champion, and 24-year-old world amateur welterweight champion Lara, were favourites for gold in Rio.
But they, as well as another Cuban competitor and trainer, defected from their national delegation.
A German-based company, Arena, on Thursday said it had signed a contract with the boxers, who are forbidden in Cuba to switch from amateur to professional.
Cuban authorities accused the company of "mafia-like" techniques to lure its athletes.
A lawyer for Arena, Rafael Villena, told the BBC he could only imagine that the two boxers had been detained for not carrying their passports on them.
Mr Villena said the boxers had been staying in Brazil to wait for a visa to travel to Germany.