Weeks after the airing of footage showing the purported execution of naked, blindfolded civilians by troops in Sri Lankan Army uniform, the Colombo government is still trying to challenge the authenticity of the video. However, experts have challenged all attempts by the government, arguing that the footage could not have been falsified.

Sri Lanka’s technological refutation of the authenticity of the video is based on a processed video-file taken from the broadcaster’s website, rather than the original mobile phone footage, experts said.

An analysis commissioned by US-based pressure group Tamils Against Genocide (TAG) of the original video distributed by Journalists for Democracy in Sri Lanka (JDS) and Sri Lanka’s subsequent technological refutation says Colombo’s experts looked “at a second generation transcoded video to derive erroneous conclusions,” reported TamilNet.

Earlier this month, Sri Lanka’s Media Centre for National Security held a press conference attempting to discredit the video, on a technical basis. Among their claims was that the video footage had been edited in a “clumsy fashion”, that one of the purportedly dead men could be seen moving after he was shot and that the entire footage was faked.

These conclusions do not challenge the authenticity of the shocking minute long video of Sri Lankan soldiers executing naked and bound prisoners, , the TAG experts said in their preliminary note.

“Sri Lanka has been putting forward spurious claims in an attempt to distract the international community from the wider issue – the mass killings of Tamil civilians by artillery bombardment as well as summary executions,” a TAG spokesperson told TamilNet.

“Personally, I think Steven Spielberg would have a hard time staging this grim scene,” Channel 4’s Foreign Affairs correspondent, Jonathon Miller, wrote on his blog.

The group who originally released the video also condemned Sri Lanka’s analysis.

This was “a piece of video evidence, where anyone can clearly see some unarmed men were been killed in cold blood by some armed men who appeared to be wearing the uniforms which are very much identical to that of the Sri Lankan army,” Journalists for Democracy in Sri Lanka (JDS) said in a statement.

“[W]hat is fake is not the video clip, but the so called ‘technical analysis’,” they said.

"It was as if someone was filming it for fun. This was being circulated by the soldiers. It has been going round for a while. It was taken as if it was a souvenir," a spokesman for JDS told reporters.

JDS is made up of journalists from Sri Lanka, from both the Sinhalese and Tamil communities, who, having fled persecution on the island, are mainly based in Europe.

Despite the Sri Lankan Government’s claims that the video is fake, it still refuses to launch an independent investigation onto the events.

This is despite having reassured the United Nations that such an investigation would be set up soon.

"We have received a guarantee from the government that it will be create an independent body to investigate such incidents. So far they have not kept [their] word. If nothing happens, we have to do something... the government has only 'weeks or months, not years, to initiate such an investigation," the UN’s Sir John Holmes said in an interview with Norway’s Aftenposten newspaper.

However, the Sri Lankan government has now started to deny the need for an independent inquiry.

Sri Lanka doesn’t “have to have so-called independent inquiries into any Tom, Dick and Harry allegation,” Professor Rajiva Wijesinha from the Sri Lankan Ministry of Disaster Management and Human Rights said, appearing on Channel 4 news to refute the video.

“This isn’t a Tom, Dick or Harry allegation. This is an allegation that the United States ambassador to the UN says gives her grave concern,” the interviewer responded, but his comment was dismissed by the Sri Lankan ministry official.

The UN Secretary General Ban Ki-Moon’s office also released a statement expressing concern about the video.

“We have viewed with utmost concern the reports and information received from various sources of serious human rights violations including those related to war crimes,” the statement said.

Philip Alston, UN Special Rapporteur on Extrajudicial, Summary or Arbitrary Executions, Susan Rice, the US Ambassador to the UN and dozens of other organisations from around the world have expressed similar concerns and called for an independent inquiry.

"These reports are very disturbing, they are of grave concern," U.S. Ambassador to the United Nations Susan Rice told reporters.

"We'd like more information as we formulate our own national response," she added.

The on-going analysis of the original video and Sri Lanka’s technological refutation was commissioned by TAG as part of the group’s wider compilation of war-crimes evidence, sources there told TamilNet.

JDS has confirmed that the original recording they distributed was recorded as a .gp3 file, and all media, including Channel-4, derived their web-broadcast versions from this, TAG said.

Sri Lanka’s technology-based refutation turn on effects that stem from the H263 (.gp3) to H264 (.avi played in Flash-9, 10) conversion process, the US experts hired by TAG say in their initial note.

“The improved algorithmic features of H264, especially the de-blocking filter at the decoder, can improve the quality of the transcoded version," the experts said.

The audio/video synchronization difference pointed to by Colombo is a known possibility of the conversion process, experts said, according to TAG.

TAG said the analysis has been commissioned as part of building a dossier of war crimes in Sri Lanka to bring about prosecutions in future.

Examination of the meta-data of the JDS version of .gp3 reveals a recording format of H263, and a recording time of 18th July 2009 UTC 9:06 a.m. (Sri Lanka Time UTC+ 5:30 = 2:36 p.m.), according to TAG.

"While JDS said that the video was likely shot in January, the video file indicates a more ominous date of 18 July, two months after the war ended with more than 300,000 Tamils held in internment camps. Implications of this are horrible to contemplate," TAG said.

“This video captures merely one instance of the summary executions and ‘disappearances’ which Sri Lanka has practised for decades,” TAG said.

“A cursory analysis of the extensive records of the SLMM shows that since 2005 Tamils have been routinely arrested or abducted, executed and their tortured bodies dumped by roads and public places across the government-controlled parts of the island,” TAG said, referring to the Sri Lanka Monitoring Mission (SLMM).

“It is the digital age that has made it possible for evidence of war crimes to seep past Sri Lanka’s information blackout,” TAG said, adding that it understands that ‘trophy’ videos of execution and torture recorded by soldiers are being traded as mementos.

JDS received the video from a Sri Lanka Army officer, said UK’s Channel 4 news, which first aired the footage. The British broadcaster broke the story and showed the video on their flagship news program on August 25.

As international alarm and outrage mounted, on September 3, the Sri Lankan government directed the Chairman of the state run Sri Lanka Rupavahini Corporation and Independent Television Network to hand over all video tapes in relation to Vanni war front immediately to the Media Minister and to ensure and verify whether any video tapes used or unused are missing or stolen while in the custody of the two institutions.