[1][2][3][4][5][6][7] Initially on 17 April 1971, 165 fighters went to India for military training including many who would later be part of this militia.

[8] Khalilur Rahman Khan led an armed group to enter Madaripur, 2 of the group's fighters were arrested during the attempt, Khalilur Rahman went to India for the second time and then re-entered Madaripur with a group of 20 members, led by Taslim Howladar, This militia changed positions multiple times, After the militia increased strength, Khalilur Rahman entered India for the third time, After his arrival was delayed, Alamgir Hossain led a force of 400 fighters, which was named as the Khalil Bahini.

Khalilur Rahman eventually returned home alive on 15 August 1971 but the name of the militia did not change.

On 10 December 1971, 40-70 Pakistani troops including 14 Razakars surrendered to Khalil Bahini.

53 Bangladeshi fighters were killed in aftermath of the battle with Pakistani troops and collaborators near the Samaddar Bridge in Madaripur-Takerhat Road.