NEW DELHI—India hanged four men convicted of the 2012 gang rape and murder of a 23-year-old student, aiming to send the message that the nation takes women’s safety seriously.

The attack, in which the woman was repeatedly raped and sexually assaulted with a metal bar on a moving bus in New Delhi before being dumped on a roadside, became one of India’s most high-profile crimes against women. The victim, who can’t be named publicly under Indian law, died in a Singapore hospital from her injuries 13 days after the attack.

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