RIO DE JANEIRO (Reuters) - A Brazilian judge provided another twist to the saga of four U.S. swimmers embroiled in a scandal at the Rio Games, suspending permission for one of the athletes, Jimmy Feigen, to leave the country - even though he had flown home hours earlier.

Feigen flew home on Friday night, police sources said, after agreeing in an earlier hearing to pay a 35,000 real ($11,000) fine for lying about being robbed at gunpoint in an incident that marred South America's first Olympics.

Prosecutors quickly appealed the penalty as being too low, persuading the judge to suspend the earlier ruling that had given Feigen the green light to leave.

The gold medalist, together with team mate Ryan Lochte, were blamed by police for falsely reporting that they had been robbed at gunpoint after a party early on Sunday.

Prosecutors had asked for a 150,000 reais ($46,800) fine for Feigen and said that the court had not followed proper legal procedure in unilaterally reducing this.

"The prosecutors office believes that 35,000 reais is not enough given the gravity and wide negative repercussions of the crime committed by the swimmer," prosecutors said in a statement received in the early hours of Saturday.

It was not clear what impact the decision might have on Feigen.

Lochte, one of the most successful Olympians of all time, issued a public apology on Friday to his fans and Olympic hosts, saying he should have been more candid in his account of the incident but was traumatized by having a gun pointed at him.

However, the youngest of the four swimmers involved in the incident, 20-year-old Gunnar Bentz, accused Lochte of playing a key role in an incident, saying he tore a poster off a wall and argued with armed security guards at a Rio gas station.

Bentz said the guards confronted them after they had urinated behind some bushes and Lochte tore the metal-framed advertising poster from the wall.

($1 = 3.2058 Brazilian reais)

(Reporting by Rodrigo Viga; Writing by Daniel Flynn; Editing by Mark Bendeich)