NEW DELHI, March 5 (Xinhua) -- The four men convicted of raping and killing a young student seven years ago will be finally hanged on March 20, ordered a court in Delhi on Thursday, after several rounds of mercy pleas from the convicts.

The infamous case happened in December 2012 when a young medical student was brutally gang-raped by six people inside a moving bus in south Delhi.

One of them committed suicide inside jail during the judicial trial, while one other was acquitted on the ground of being a juvenile.

The rest four, namely Pawan Gupta, Vinay Sharma, Akshay Thakur, and Mukesh Singh have been facing trial for the past seven years and their execution has been deferred three times already in recent months.

Each of them moved mercy and review petitions at different forums, including the courts of law and the president of India, over the past few weeks.

The court set the first date of hanging on Jan. 22 and the third one on March 3.

However, the four convicts managed to avoid the gallows by moving fresh applications requesting for mercy on one ground or the other.

The victim Nirbhaya's mother Asha Devi told the media that she hoped March 20 would be the final execution date.