The 82-year-old Abdul Jabbar, a member of parliament in the 1980s for the government-aligned Jatiya Party, was tried in absentia, as he is thought to have fled to the United States.
Enayetur Rahim, a war crimes tribunal judge, sentenced Jabbar to life in prison after finding him guilty of five charges of atrocities committed during the nine-month war against Pakistan, the prosecutor said.
“He was found guilty of all five charges including genocide, murder, arson and religious persecution,” Zahid Imam told AFP.
“He was involved in murdering 36 people and forcibly converted 200 Hindus to Islam.”
Jabbar is the 18th person convicted by the International Crimes Tribunal, a domestic court set up by the government.
Prosecutors said Jabbar was the head of a pro-Pakistani militia in the coastal town of Mathbaria and collaborated with the Pakistan army during the conflict when then-East Pakistan seceded from Islamabad.
The tribunal has mostly focused on the trials of Islamist leaders who opposed the break up of Pakistan and saw the liberation war by Bengalis as a conspiracy by majority-Hindu India.
Leaders of the Jamaat-e-Islami party were in 2013 sentenced to death by the tribunal for their roles in the conflict, plunging Bangladesh into its worst unrest since independence.
Jamaat says the trials are aimed at eliminating opposition leaders rather than rendering justice while rights groups have said they fall short of international standards.
The government maintains they are needed to heal the wounds of the war, which it says left three million people dead. Independent researchers put the toll much lower. -AFP