Yesterday, the men were convicted under a new legal provision that punishes repeat offenders in rape cases with a life term or death sentence.
Vijay Jadhav, 19, Kasim Bengali, 21, and Salim Ansari, 28, are the first to be sentenced to death for rape not involving the death of the victim, as part of stronger laws enacted after the fatal gang-rape of a young student in Delhi in December, 2012. A fourth convict, Siraj Khan, has been sentenced to life in jail and a minor accused is being tried separately.
"Any leniency in this case would be a travesty of justice. There needs to be zero tolerance for such crimes. The message needs to be loud and clear," said Judge Shalini Phansalkar Joshi.
The three men were the common factor in the gang-rapes of a photojournalist and a telephone operator in the deserted mill in the heart of Mumbai, which dented the city's image as one of India's safest.
They were described as unemployed school dropouts known for petty thefts, who used to drink and spend time at Shakti Mills. The prosecution told the court that when they spotted the photojournalist and her colleague on August 22, they called two of their friends saying, "Come. The shikar (prey) has arrived."
The 23-year-old photographer was on assignment at the mill when five men tied up her colleague and took turns to assault her, holding a broken bottle to her head. The attackers were found guilty of offences that included showing pornography to her and forcing her to perform similar acts, stripping her, and destroying evidence.
The phone operator came forward after learning of the photographer's ordeal. She revealed that the same men had raped her nearly a month before, on July 31.
Prosecution lawyer Ujjwal Nikam told the court that after repeatedly raping the photojournalist, they laughed at her and boasted, "We are evil. We have raped many girls but no one has ever caught us."
Mr Nikam said, "This shows that they were not afraid of the law."