We need a UN sponsored investigation to find the exact history of what happened. Then people in both countries can discuss what do about it.
What I have uncovered so far:
Bengali's in then East Pakistan were not traitors, that is a myth that the military govt. headed by Ayub Khan tried to establish by framing Mujib, as Mujib was getting too powerful with his 6 point demand for autonomy, but the framing backfired when Bhasani ran a mass movement to expose it and free Mujib. Agartala case however, was a true conspiracy of very small scale hatched by RAW with some minor people where Mujib was not involved. Ayub Khan wanted to use this minor case to falsely frame Mujib.
When Mujib won the election, Yahya Khan and some of his generals planned Operation searchlight (some refused to take part and resigned), instead of giving power to the elected Awami League govt.
Mujib was no Indian agent till 1971, but he betrayed his people after 1971 and shook India's hand, so he can make Bangladesh his personal property using India's help.
Much of the pro-India b*tards we face today in Bangladesh, it is precisely because India found an opportunity to get into Bangladesh affairs, due to Operation searchlight and the resulting mass revolt and war in 1971. It is possible that there were instigation by Indian infiltrators or their agents before that, but it was very small scale and Operation searchlight was not necessary to solve that, in my personal opinion.
So my request to Pakistani's, please do not insult Bangladesh or Bangladeshi's by calling them traitors or someone that cannot be believed. It was rather an Army who we believed to be our own Army that started killing our own people in a systematic planned way to teach the population a lesson of not getting too uppity. The question should be raised why did they think this way? They thought Bengali's to be inferior race, so they should know their place?