Rio de Janeiro(CNN) US Olympic swimmer Ryan Lochte apologized Friday for his behavior with three of his teammates over the weekend at a Rio de Janeiro gas station, where police said at least one of the men vandalized the business and urinated on the premises.

Lochte had originally said that he and fellow swimmers James Feigen, Jack Conger and Gunnar Bentz were pulled over in their taxi and robbed at gunpoint early Sunday, but police deny a robbery took place.

Can Brazil get Ryan Lochte extradited?

"I wanted to apologize for my behavior last weekend -- for not being more careful and candid in how I described the events of that early morning and for my role in taking the focus away from the many athletes fulfilling their dreams of participating in the Olympics," he said Friday on Instagram.

A photo posted by Ryanlochte (@ryanlochte)

He said he accepted responsibility for his role in the case and had "learned some valuable lessons."

How it happened, when it happened

He did not, however, roll back on his allegations the swimmers had been robbed at gunpoint by men posing as police.

Police said that security guards used guns to control the athletes, adding that the Americans were drunk, and took 100 reais ($20) to cover the damage the men caused.

"It's traumatic to be out late with your friends in a foreign country -- with a language barrier -- and have a stranger point a gun at you and demand money to let you leave," Lochte said in his on Instagram post.

"I should have been much more responsible in how I handled myself and for that am sorry to my teammates, my fans, my fellow competitors, my sponsors, and the hosts of this great event. I am very proud to represent my country in Olympic competition and this was a situation that could and should have been avoided."

The public had awaited Lochte's response after the release of closed-circuit TV footage Thursday that appeared to support at least some of the police's assertions.

Lochte omitted details that led up to what he called a robbery, some of which appeared in the video footage.

But his apology and the video still do not clear up the biggest question -- were the swimmers robbed?

Lochte and police do all agree on one thing: A gun was brandished, and money exchanged hands.

The stories, however, seem to diverge at a single point -- when Lochte re-entered a taxi after stopping at the station.

The apology may bring the six-day mystery to a close in a case that quickly spiraled into an international matter involving consular officials, lawyers and judicial orders.

On Wednesday night, authorities took the extraordinary step of pulling Conger and Bentz from their flight home for questioning. The pair returned to Miami on Friday morning.

Jack Conger and Gunnar Bentz arrive back on home soil

Police said the men denied there was robbery and Lochte's account of events, but they have not yet made a public statement.

Police said in a statement on Facebook that that Feigen had agreed to make a 35,000 reais (nearly $11,000) contribution to a Brazilian charity organization.

The decision was made, police said, in a court appearance to answer accusations that the swimmers had made false claims they were robbed.

US Olympic Committee apologizes

The US Olympic Committee earlier apologized on for the athletes' behavior after the video footage came to light.

"On behalf of the United States Olympic Committee, we apologize to our hosts in Rio and the people of Brazil for this distracting ordeal in the midst of what should rightly be a celebration of excellence," a committee statement said.

The statement said that an "argument ensued between the athletes and two armed gas station security staff, who displayed their weapons, ordered the athletes from their vehicle and demanded the athletes provide a monetary payment. Once the security officials received money from the athletes, the athletes were allowed to leave."

Rio Mayor Eduardo Paes said Friday he felt "pity and contempt" for the swimmers, saying he accepted the US committee's apology.

"I believe that all of us need to accept the apologies of the US Olympic Committee, the same way our Olympic Committee would have had to apologize if the assault had occurred. The apologies have been more than accepted," he said.

The incident gave to a hashtag battle on social media, with some referring to it as #LochteGate and others preferring #Lochtemess.

Twitter users were divided, with some throwing their support behind the champion swimmer and others branding him a liar.

Lochte has also borne the brunt of negative media coverage, many reports accusing him of being a liar.

The New York Post depicted Lochte on its front cover Friday under the words "Liar, liar, Speedo on fire" and above the headline "The Ugly American".

Charges unlikely, police say

Though the US committee apologized, the statement still largely corroborates Lochte's account: The four were in a taxi, a gun was brandished and money was exchanged.

Lochte's attorney, Jeff Ostrow, said the incident still amounted to a robbery and the new information and video did not change that view.

The police early on appeared to have doubts about the 32-year-old swimmer's veracity.

First, they learned on social media that four Americans had reportedly been mugged -- a story Lochte told in hair-raising detail to the US media -- civil police Chief Fernando Veloso said at a press conference Thursday.

They tracked down witnesses, including three of Lochte's fellow swimmers at the scene, reviewed surveillance tapes and made a ruling on whether the accounts looked or sounded like a robbery.

"The surveillance tapes show that there was no violence against the athletes at the gas station," Veloso said. "Their claim that they are a victim of an assault or robbery or any kind of violence is not true."

Veloso said the other swimmers say it was Lochte, who created the lie. "The only person that continues to say there was a robbery is (Lochte)," Velso said after the press conference.

The investigation showed security guards stopped the athletes from leaving the station until police could be called. One pulled a gun on Lochte after he became angrily confrontational, Veloso said.

But Veloso insisted there was no evidence the guard's actions were unreasonable.

Two sources told CNN the exchange of money at the gas station was not a negotiation. The guards made a money gesture with their hands and regardless of how it started, the swimmers had a gun pointed at them and they were not allowed to leave until they had given the money, the sources said.

The sources said the athletes admitted urinating behind the building and then the men showed up and one held up a badge. Soon the athletes were handing over money, although the sources did not say how much.