The female photographer with an English language magazine was assaulted by five men in the Indian capital on Thursday evening, undercutting the citys image as a place where women can safely move about in public spaces.
The crime echoed the gang rape and murder of a woman in New Delhi in December, which set off an unprecedented wave of protests.
The woman, 22, arrived at the abandoned compound of Shakti Mills, a defunct textile factory, around 6 p.m., accompanied by a male colleague. She was taking photographs of the area, now a trendy hub for media and advertising companies, for a magazine article about Mumbais tenements for workers who were once employed in the mills.
Under Indian law, the authorities may not release the name of a rape victim or, in this case, the name of her employer.
The authorities said that five men accosted and assaulted the two journalists inside the compound. The male journalist was tied up and beaten before the young woman was raped. Doctors said she had suffered external and internal injuries but that she was expected to recover.
On Friday morning, in an unusually rapid response, the Mumbai police arrested one of the five attackers, and the police said they had identified the others.
One of the five has been arrested and he admitted he was there along with some others, Singh said at a news conference Friday afternoon. The police have released sketches of the five men.
While Mumbai, Indias financial capital, is widely considered one of the countrys safest cities, recent events have brought that into question. According to statistics from the Praja Foundation, a nonprofit organization in Mumbai, 207 rape cases were registered in the city in 2011 and 2012, a 15 percent increase over 2010.
The number of rapes reported in India is believed to be much lower than the actual number.
The assault on the journalist has triggered outrage and intense anger in the Indian news media.