A late night outing turned into a six-hour-long nightmare after an American woman was gang raped and beaten aboard a public transit van while her handcuffed French boyfriend looked on helplessly, in an incident that’s shocked this resort city as it gears up to host next year’s World Cup and the 2016 Olympics.

The police response to the attack was swift: The three alleged perpetrators, aged 20 to 22, have all been taken into custody, and investigators are combing databases to determine whether the men might have been behind any other crimes.

Many still ask whether Rio authorities, who have succeeded in cracking down on much of the city’s drug violence, are up to the task of protecting the waves of tourists expected to flood the city during the upcoming double-header of mega-events. Some 2 million people are also expected to flock to the city in late July for World Youth Day, a Roman Catholic pilgrimage that Pope Francis is scheduled to attend.

Some observers said the attack came as a particular shock given that safety has improved at least in the city’s tourist-friendly, seaside South Zone neighborhoods. Foreigners and moneyed local residents who even three or four years ago would have hesitated to hail a taxi in the street or walk around after dark now do both without thinking twice.

“No one expects to be attacked in Disneyland, handcuffed and roughed up,” Globo newspaper quoted Alfredo Lopes, the head of an association representing Brazil’s hotel sector. “Copacabana is our Disneyland.”

Yet it was in that very beachfront neighborhood, full of senior citizens in bikinis by day but seedier by night, that the two foreigners hailed one of the fleet of public transit vans often used as a speedier alternative to buses. Police investigating the case say the two foreigners, both in their early-20s, were headed shortly after midnight Saturday to Lapa, a popular downtown nightlife hotspot where Rio’s youth converges on clubs, bars and samba venues.

But the pair never made it to their destination. A few minutes into their journey, the van operators forced the other passengers off and inflicted on the two foreigners what Alexandre Braga, the police officer leading the investigation, has called a “party of evil.”

The three assailants took turns raping the woman and beating the man, whom they handcuffed and sometimes struck with a metal crowbar, Braga told a news conference Tuesday.

“The victims recognized the three without a shadow of a doubt,” Braga said. The men’s mug shots were also recognized by another woman who said she’d been raped by the three under similar circumstances last month. Another foreigner has said she’d been robbed by one of the three suspects, police said.

Two of the suspects have confessed to Saturday’s attack, while the third denies any responsibility.

“They do not show any repentance,” Braga said. “They are quite indifferent, cold.”

Walter Maierovitch, Brazil’s former drug czar and an organized crime expert, said that with crime down overall, one of the city’s main challenges will be making sure visitors remain vigilant and aware of basic safety precautions.

“There has been a lot of improvement in Rio but there is still a lot more to be done in terms of security, mainly more preventive actions, alerting tourists both foreign and domestic of the precautions they should take, neighborhoods to avoid,” he said.

He added that Saturday’s attack “was a setback, but in terms of image and security I don’t think it is a major or long-lasting one that will scare tourists away from Rio.”