A night out on the town turned into a nightmare when an American woman was gang raped and beaten aboard a public transport van while her French boyfriend was handcuffed, hit with a crowbar and forced to watch the attack, police said.

The incident raises new questions about security in Rio, which has won kudos for its crackdown on once-endemic drug violence in preparation for hosting next year’s football World Cup and the 2016 Summer Olympic games. The city also will be playing host to World Youth Day, a Roman Catholic pilgrimage that will be attended by Pope Francis and is expected to draw some 2 million people in late July.

Three men aged 20 to 22 are being held in connection to the crime, which took place over six hours starting shortly after midnight Saturday, police said. The suspects have been accused of at least one similar attack, with a young Brazilian woman having come forward to say that she too was raped by the same men in the van on March 23, police said.

“The victims described everything in great detail, mostly the sexual violence,” police officer Rodrigo Brant told the Globo TV network. “Just how they described the facts was shocking — the violence and brutality. It surprised even us, who work in security and are used to hearing such things.”

The attack drew comparisons to the fatal December beating and gang rape of a young woman on a New Delhi bus in which six men beset a 23-year-old university student and male friend after they boarded a private bus. That attack touched off a wave of protests across India demanding stronger protection for women. Officials there say tourism has dropped in the country following the attacks.

On Tuesday, Brazilian police were quick to emphasize to reporters the rarity of Saturday’s attack.

“These type of crimes committed against foreign tourists are very uncommon,” said Alexandre Braga, the police officer leading the investigation.

Officials from the local Olympic and World Cup organizing committees didn’t immediately respond to requests for comment about how the attack might affect their security precautions.

Braga said the two foreigners, who were in Brazil as students, took a public transport van similar to those often used as a faster alternative to the city’s bus fleet. The pair were heading from Rio’s Copacabana beach neighborhood to the nightlife hot spot of Lapa in downtown Rio.

A few minutes into the ride, the suspects forced the other passengers to get out of the van and then raped the female tourist inside the moving vehicle, Braga said. The woman was also beaten across the face, and the man was handcuffed and beaten, at one point with a metal crowbar.

The three suspects took turns behind the wheel, driving the van to Rio’s sister city of Niteroi where they went on a spending spree with the foreigners’ credit cards.

Once they hit the limit on both cards, spending around $500 at gas stations and convenience stores, the suspects drove the pair back to Rio, where the foreigners were staying, and forced the woman to fetch another credit card, Braga said.

Although she was alone, she didn’t call the police or alert anyone, Braga said, “because the young man was still under the suspects’ control and she feared something even worse might happen to him.”

The two were ultimately dumped by the side of a highway near the city of Itaborai. After they managed to make it to an unidentified country’s consulate, officials took the two to the special police delegation that specializes in crimes against foreigners. The young woman has returned to the U.S., while the man remains in Rio to help with the investigations, Braga said.