Four Olympic swimmers from Team USA, who said they had been robbed in Rio de Janeiro, were not victims of crime, the head of the city’s civil police has said.

Fernando Veloso told reporters that one or more of the men had committed an act of vandalism at a petrol station and then offered to pay for the damage.

The Americans paid and left after armed security guards intervened, he said.

One guard had drawn his gun after one of the swimmers began behaving erratically, Fernando Veloso added.

Three of the swimmers, Gunnar Bentz, Jack Conger and James Feigen, remain in Brazil and are being questioned by police. The fourth, gold medalist Ryan Lochte, returned to the United States on August 15.

Gunnar Bentz and Jack Conger were taken off a US-bound plane at Rio de Janeiro airport on August 17 and were seen entering a Rio police station for questioning on August 18.

According to police, the swimmers invented a story about a robbery to disguise a dispute over a damaged bathroom door at the petrol station.

The men, who have repeatedly changed their accounts of what happened, could “in theory” face charges of giving false testimony and vandalism, Fernando Veloso said.

“We are dealing with important public figures who influence others and should know how to comport themselves,” he told reporters during a news conference at Rio police HQ.

The people of Rio de Janeiro were unhappy to see the reputation of their city damaged, Fernando Veloso said, adding: “An apology would be welcomed.”

Video from CCTV appears to show the athletes being detained and ordered to sit on the ground.

Ryan Lochte admitted on August 17 to some inaccuracies in his original account of being robbed at gunpoint in the early hours of Sunday, but vehemently denied making the story up.

“I wouldn’t make up a story like this nor would the others – as a matter of fact we all feel it makes us look bad,” he told NBC.

Accounts of what happened to the swimmers have been confusing from the beginning.

News of the incident emerged after Ryan Lochte’s mother told US media about it.

Ryan Lochte himself gave an initial account of the events to NBC on August 14, saying he and the other swimmers had been in a cab returning from a club in the early hours when they were pulled over by men wearing police badges.

He said they had pulled a gun and told the swimmers to get on the ground. “I refused… and then the guy pulled out his gun, he cocked it, put it to my forehead…”

Ryan Lochte has since slightly altered his account, telling NBC on August 17 that the cab had not been asked to pull over – they had been robbed while making a stop at a petrol station – and he said the gun had not been pointed directly at his forehead.

He called the inconsistencies a “traumatic mischaracterization” caused by the stress of the incident.

Police and the judge investigating the case found inconsistencies in the men’s accounts.

CCTV footage of their return to the athletes’ village appears to show the swimmers laughing and joking, and handing over their wallets, phones and accreditation, as they go through the security screens. The judge said they had not shown signs of being affected by a robbery.

Ryan Lochte is one of the most successful swimmers in history, with 12 Olympic medals, and he once had his own reality TV show in the US. In Rio, he swam in two events, winning gold in the 4x200m freestyle relay.

James Feigen won gold in the 4x100m freestyle relay.

Gunnar Bentz competed in the 4x200m preliminaries, but not the final. He still received a gold medal after the US team’s win.