Yes, it’s true, I’m part Bengali and my mum was living in Bangladesh during the war (the Indian army even took over their house) and some of the stuff that went on back then was horrendous..
One thing she told me that stuck in my mind was about a group of female students at Dhaka University who were held and gang-raped, basically used as sex-slaves.. in fact after the war the Gov launched an initiative to try and persuade men to marry women who had gotten pregnant by Pak soldiers during the war 
I know this stuff happens in every war but doesn’t make it any more acceptable to me.. Another thing that happened was that the local religious groups would give hit lists of academics and the more successful families in their areas for the Pakistani army to hunt down and kill. This is one reason the religious parties are still not popular in Bangladesh as a lot of people still resent and don’t trust them due to what they did back then (there’s one very famous religious guy whose name I can’t remember who even now says that Bangladesh should be part of Pakistan)..
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