MUMBAI, India — At 5:30 p.m. on that Thursday, four young men were playing cards, as usual, when Mohammed Kasim Sheikh’s cellphone rang and he announced that it was time to go hunting. Prey had been spotted, he told a friend. When the host asked what they were going to hunt, he said, “A beautiful deer.”

As two men rushed out, the host smirked, figuring they did not like losing at cards.

Two hours later, a 22-year-old photojournalist limped out of a ruined building. She had been raped repeatedly by five men, asked by one to re-enact pornographic acts displayed on a cellphone. After she left, the men dispersed to their wives or mothers, if they had them; it was dinnertime. None of their previous victims had gone to the police. Why should this one?

The trial in the Mumbai gang-rape case has opened to a drowsy and ill-attended courtroom, without the crush of reporters who documented every twist in a similar case in New Delhi in which a woman died after being gang-raped on a private bus. The accused, barefoot, sit on a bench at the back of the courtroom, observing the arguments with blank expressions, as if they were being conducted in Mandarin. All have pleaded not guilty. They are slight men with ordinary faces, nothing imposing, the kind one might see at any bus stop or tea stall.

But the Mumbai case provides an unusual glimpse into a group of bored young men who had committed the same crime often enough to develop a routine. The police say the men had committed at least five rapes in the same spot. Their casual confidence reinforces the notion that rape has been a largely invisible crime here, where convictions are infrequent and victims silently go away. Not until their arrest, at a moment when sexual violence has grabbed headlines and risen to the top of the state’s agenda, did the seriousness of the crime sink in.