NEW DELHI - Indian police arrested four men, including a bell boy of a five-star hotel in the national capital, on Monday for allegedly raping an American tourist in April, police said, highlighting the dangers faced by women in the country from violent sex attacks.

The 25-year-old tourist, who had made a complaint in October, returned to India recently to depose before a magistrate and identify the accused, the Times of India newspaper reported.

After receiving a complaint from a US-based NGO on behalf of the victim, followed by her written complaint earlier this month, the Delhi police have arrested four men, Dependra Pathak, joint commissioner of Delhi Police, told reporters.

"We are interrogating four persons while the fifth accused still has to be identified and arrested," he said, adding in the next day or two the police could parade the accused for identification by the victim, with the court's permission.

According to Pathak, in her statement, the women said five persons drugged and sexually assaulted her inside her hotel room after she checked in. She said they offered her water laced with sedatives, and sexually assaulted her on two separate days, Pathak said.

She left India after the incident and said it was only towards the end of July that she started to remember what had happened to her, he said.

Pathak said the NGO and a law firm complained initially about her harassment in October, but later the police found it was a case of a rape and forwarded the case to the local police in November.

"We ourselves approached her and requested her to mail her complaint," he said while denying accusations by the Delhi Commission for Women, an independent body, of delay in the arrest of the accused.

Sex crimes are common in India. The National Crime Record Bureau says more than 34,000 rapes were reported across the country in 2015, including about 2,000 cases in the national capital New Delhi.

Indian authorities are facing sustained criticism for not doing enough to address a weak system of law enforcement and policing that leaves women vulnerable to sex crimes.