The three other US swimmers were lying on the ground, following their assailant's orders, when the gunman turned to Ryan Lochte, one of Team USA's charming stars.
"I'm not getting on the ground," Lochte said, as he recounted to NBC News the story of the armed robbery he endured early Sunday morning. "And then the guy pulled out his gun, he cocked it, put it to my forehead and he said, 'Get down', and I put my hands up. I was like, 'Whatever'."
The four swimmers on the US Olympic team lost their money and wallets but otherwise escaped unharmed from the gunmen who were posing as police officers.
The harrowing assault, however, amounts to the most serious breach of security against American athletes in these Olympics, and it follows a troubling pattern of robbery, gunfire and assaults that call into question the ability of Brazil's security forces to keep participants and fans safe.
Lochte, who won a gold medal as part of a relay in these Games, had been travelling home in a taxi, heading to the Olympic Village after a dance party, along with teammates Gunnar Bentz, Jimmy Feigen and Jack Conger, when the robbery occurred, according to the US Olympic Committee. Lochte told NBC that after the taxi pulled over, men approached them with a police badge.
"They pulled out their guns, they told the other swimmers to get down on the ground - they got down on the ground," Lochte said. "I refused. I was like we didn't do anything wrong, so - I'm not getting down on the ground." After the man threatened him with the gun, Lochte said, "He took our money, he took my wallet - he left my cellphone, he left my credentials."
The four swimmers made it home unharmed. One of the swimmers, Conger "is safe and in Rio", said his mother, Bridget.
"We are all safe," Bentz tweeted. "Thank you for your love and support. PS: The gold medal is safe," he added.
After four Olympics, Lochte, 32, has established himself as one of the more colourful athletes representing the US. At the London Olympics he flashed a custom-made American flag dental grill. In Rio he died his hair silver. Lochte has the reputation as a bon vivant but has also emerged as an elder statesman with the swim team. He has won six gold medals, including one in Rio for the 4x200m freestyle relay.
Late in the evening, Lochte attended a party with Brazilian swimmer Thiago Pereira and Pereira's wife, Gabriela Pauletti, at Club France in an upscale neighbourhood of Rio, according to Flavio Perez, a representative for Pereira. Some 2500 attended the DJed dance party, which began around 11.30pm.
A spokesman for Club France said that Lochte and Pereira left the party between 2.30-3am. But Perez said that Pereira and his wife went back to their hotel earlier. It is unclear whether the other three US swimmers attended the party or met up later.
Word of the robbery touched off a chain of confusion between Olympic and US officials. An International Olympic Committee spokesman said reports of the robbery were "absolutely not true," then reversed himself, apologised and said he was relying on initial information from the USOC that was wrong.
After interviewing one of the swimmers, police said that the athletes had been returning from the party in the taxi when they were robbed but "the victim did not know where the robbery happened". One police officer said that taxi drivers often work with other criminals to assist robberies. The prospect of thieves dressed as police is more unusual, the officer said.
"From my point of view, the taxi diver was involved. Very possible."