To execute their plan he along with Beant Singh decided to commit this crime i the very next morning. So, around  9'o clock of 31 October 1984  when Indira Gandhi walked from her house to her office at Safardajung Road, Satwant Singh and Beant Singh assassinated her.

They did not stop after firing one or two rounds; they fired almost thirty three bullets into her chest and abdomen. At first Beant Singh took out his .38-calibre revolver and fired three shots into Indira Gandhi's abdomen. It wasn't over yet for them. When they saw her falling unconscious on the ground Satwant Singh again fired 30 rounds from his Sten submachine gun into her body. After killing her both of them shouted Sikh religious slogan “Bole So Nihal, Sat Sri Akal”.

After the work was accomplished both of them placed their weapon on the ground saying to each other that they have done their respective job. Later, they were taken into custody and taken to the guardhouse where a struggle followed up in which Satwant Singh supposedly grabbed the commando's handgun and other commandos too started fire.

Beant Singh died from the gunshot wounds sustained in the room whilst Satwant Singh was badly injured and on the arrival of the senior security officer was taken to a hospital.

Satwant Singh was awarded death sentence, along with Kehar Singh who had hatched the conspiracy ans was the uncle of Beant Singh.

Here goes the details of the three persons involved in the assassination of Prime Minister Indira Gandhi: