NEW DELHI -- Indian police said Monday that they arrested four men on suspicion of raping an American tourist who came to New Delhi alone earlier this year, marking another incident of sexual violence to stir outrage.

Police Officer Rakesh Kumar said the suspects -- a tour guide and his associate, a car driver and a hotel worker -- were arrested Monday.

The woman said in her police complaint that the four men raped her after she was drugged in a New Delhi hotel room in April. They denied the accusations.

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She also said the four men had shot a video of the attack and had threatened to make it public if she reported the matter to anyone, police said.

The woman went back to the U.S. and registered a complaint through an email to New Delhi’s police commissioner. She returned to the Indian capital earlier this month to pursue the case because she was dissatisfied with the progress of police investigation.

The Press Trust of India news agency said the police did not arrest the four men earlier because the travel agency they worked for conducted an internal inquiry and gave them a clean chit.

The suspects also told investigators during questioning that the woman was trying to falsely implicate them because she had gone with them to Agra to see the Taj Mahal, the monument of love, a day after accusing them of the crime, PTI said.

The case highlights the persistent violence against women in India despite tougher laws against sexual assault imposed after the December 2012 death of a young woman who was gang-raped on a bus in New Delhi.