Full coverage: 2016 Rio Olympics

Brazilian police continue to investigate an alleged robbery involving U.S. swimmer Ryan Lochte and three younger teammates.

The six-time Olympic gold medalist has already returned home, but his compatriots are having their stay in Rio extended while local authorities probe their claims of being held up at gunpoint by criminals dressed as cops in the early hours of Sunday morning.

Jimmy Feigen was prevented from boarding a flight to the U.S., while Jack Conger and Gunnar Bentz left the airport after being pulled off their plane.

Lochte departed Brazil before a judge issued an order to seize the foursome’s passports and keep them in the country until they testify about the incident.

Law enforcement officials say they want to clear up several discrepancies in the swimmers’ stories.