A European team was in Bangladesh for an international probe into countless killings by the Pakistani army in 1971 amid calls to declare the atrocities the worst genocide since World War II.
Campaigners hailed the 20-26 May Dutch-led mission as a recognition of efforts to bring to justice those responsible for 3 million deaths, 200,000 rapes and exodus of 10 million Bangladeshis to India.
The team - which includes British security expert Chris Blackburn, Dutch genocide scientist Anthonie Holslag and several others - will report to the Netherland government and parliament in The Hague.
Team leader and former MP Harry Van Bommel accused Washington of turning a blind eye to the slaughter because of its support to Cold War ally Pakistan.
"West's friendship with Pakistan is the reason for this dilemma," he said on the sidelines of a conference on the atrocity that began in March 1971 and ended nine months later when India sent its military into what was then East Pakistan.
"Even if it takes a hundred years to get global recognition of the Armenian Genocide, I hope it will not take that long in the case of Bangladeshi genocide.
"We want to have it within a few years, not even decades."
Bommel was speaking in the capital Dhaka, which saw the worst violence after troops on 25 March, 1971, began exterminating university students, professors and critics of the regime in Islamabad.
Bangladesh, which marks 25 March as Genocide Remembrance Day, has been calling for global recognition of the killings.
In October 2022, two US Congressmen tabled legislation that declared the atrocities against ethnic Bengalis as "crimes against humanity, war crimes, and genocide".
The British parliament has condemned the action in East Pakistan, while France has encouraged Dhaka to research and document the atrocities.
Bilateral ties bloomed ever since the Netherlands became one of the first European nations to recognise Bangladesh as a sovereign state a year after it was carved out from Pakistan's eastern rump in 1971.
The Bangladesh event is counted as India's most successful military campaign against rival Pakistan, which capitulated after 93,000 of its soldiers surrendered 17 days after a full-scale war erupted on 3 December 1971.
But war veterans and diplomats say Pakistan, which fought two more unsuccessful wars with India, must learn its lessons.
"The time has come to bring them to book and we, not only as Indians but the whole of humanity, should spit on them for their dirty affairs," said retired Indian army colonel VK Sahni.
While Prime Minister Sheikh Hasina has acted swiftly against war criminals, many of those who plotted the killing of Sheikh Mujibur Rahman, a former Bangladesh president and her father, have fled to the West.
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"She is talking continuously with governments of the US and Canada where individuals who have been declared guilty of the murder of her father in a fair trial in Bangladesh are now living for long years," said Indian diplomat Veena Sikri during a discussion on the genocide.
"So this is a very very serious matter and there has to be a full and complete closure."
Three-star general GG Dwivedi said he saw signs of the atrocities, including Bangladeshi women held as "sex slaves" in battle bunkers, while in Dhaka as a young lieutenant.
In an interview with NewsX TV, Dwivedi compared the genocide to the Holocaust, adding the "Pakistani army got away with it".
"The people tried in Bangladesh were mere collaborators but the real perpetrators got away scot free and so it comes as a great relief that now the investigation has been opened up again."