A government-appointed Sri Lankan judge says allegations the army committed war crimes during the long conflict with Tamil Tiger rebels are "credible".
He was leading the first government inquiry into the atrocities, one month after the UN released its own findings.
President Maithripala Sirisena has already vowed to set up a truth and reconciliation commission to investigate further.
The 26-year war left at least 100,000 people dead.
The UK's Channel 4 and the UN have documented numerous atrocitiescommitted during the war, with one investigation saying up to 40,000 people may have been in killed in the final five months alone.
Others suggest the number of deaths could be even higher.
'White Flag' caseRetired judge Maxwell Paranagama told Sri Lanka's parliament on Tuesday there were "credible allegations which...may show that some members of the armed forces committed acts during the final phase of the war that amounted to war crimes giving rise to individual criminal responsibility".
He went to say there was evidence to suggest that footage obtained by the Channel 4 documentary "No Fire Zone" showing prisoners naked, blindfolded, with arms tied and shot dead by soldiers was genuine.
Sri Lanka's military at the time had dismissed the documentary as a fabrication.
The Paranagama commission also said a case involving the killing of top Tamil political leadership in May 2009 - known as the "White Flag" case - should be investigated.
He called on the government to set up an internationally-backed judicial inquiry, which was also recommended in the UN report in September.
The first government-led inquiry into the allegations was commissioned in 2013 by then-President Mahinda Rajapakse, who oversaw the final push against the rebels in 2009.
Mr Rajapaksa has always denied his troops committed war crimes, and resisted international inquiries.
The UN's a long-awaited report accused both sides of atrocities, especially during the final stages of the war in 2009.
Its main findings include:
While government forces were accused of indiscriminate shelling leading to massive casualties, the Tamil Tiger rebels were alleged to have used civilians as human shields and shot people trying to escape.
Allegations persist to this day that the army killed rebel leaders and others after they surrendered or were captured - and the UN admitted in 2012 that it could and should have done more to protect civilians.
As well as the thousands of Tamils who died in the final battles near Mullaitivu, many others are still missing.
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