A series of photographs show Balachandran Prabhakaran, son of Villupillai Prabhakaran, who was head of the Liberation Tigers of Tamil Eelam (LTTE).
According to the Independent, one of the photos shows the boy sitting in a bunker, alive and unharmed, apparently in the custody of Sri Lankan troops.
Another picture which was taken a few hours later shows the boy's body lying on the ground, his chest pierced by bullets.
The images were taken in May 2009 at the end of the Sri Lankan Government's operation to crush the LTTE, which had launched a bloody, decades-long insurgency against the state that led to the deaths of perhaps 70,000 people.
According to the report, the authorities always said Prabhakaran's son was killed in cross-fire, as troops moved in to take the LTTE's last stronghold.
But the images, contained in a new documentary, No Fire Zone, which will be screened at the Geneva Human Rights Film Festival during the UN Human Rights Council meeting in March, suggest the boy was captured alive and killed at a later stage.
A forensic pathologist who examined the later images for the film-makers, said the boy was shot five times in the chest.
Furthermore, propellant burns around the wound suggest he was shot at very close range.
The film's director, Callum Macrae, claimed that the new photographs were important evidence because they appear to rule out any suggestion that Balachandran was killed in cross-fire or during a battle.
They show he was held, and even given a snack, before being taken and executed in cold blood.
Prabhakaran's body was displayed on state television, part of the front of his skull missing, also suggesting he may have been shot at close range.
The Sri Lankan authorities have always denied shooting anyone who was trying to surrender, it added.
London: Fresh questions have been raised over Sri Lanka's armed forces conduct during the final stages of the operation against Tamil Tiger rebels after new photographs emerged claiming that the 12-year-old son of the militants' leader was summarily executed.
First Published: Tuesday, February 19, 2013, 11:52