Campaigners have called for a fresh autopsy of historic IRA leader Michael Collins almost 100 years after his assassination.
Mystery has long surrounded his killing on August 22, 1922, when he was shot in the head near Beal na Blath in County Cork, during Ireland's Civil War.
But new evidence about a suspect has led historians and forensic scientists to re-examine the case, with some calling for his body to be exhumed.
An upcoming documentary - Cold Case Collins - by state broadcaster RTE, will see detectives and experts, including retired state pathologist Prof Marie Cassidy, examine the evidence.
'We should exhume the body and find out the nature of the wounds, otherwise we'll be talking about this for another century,' Paddy Cullivan, an academic turned film-maker, told the Guardian.
Mystery has long surrounded the killing of Michael Collins (pictured) on August 22, 1922, when he was shot in the head near Beal na Blath in County Cork, during Ireland's Civil War
Collins led the original Irish Republican Army (IRA) as it took on British forces during Ireland's war of independence between 1919 and 1921.
He managed to bring the Brits to a stalemate, forcing them into negotiations which ended with a treaty that freed 26 of Ireland's 32 counties.
Collins was appointed Chairman and Minister of Finance of the provisional government which was responsible for the establishment of the Irish Free State.
He played a decisive role in devising a constitution, creating security forces and appointing a civil service.
However some IRA members refused to accept the deal with the Brits, leading to a civil war.
Collins was murdered aged 31 while on an inspection tour of Munster and searching for a basis for peace with IRA leaders opposed to the Treaty.
His convoy was ambushed and he was killed by a bullet to the head when he got out of his car to return fire.
But the lack of an inquiry or death certificate - and a lost autopsy report - has shrouded the death in mystery for almost a century.
Most agree that someone from the ambushing group fired the fatal bullet, however there are a range of theories as to the identity of the shooter.
Some posit the killing was the work of a skilled sniper given the shot was fired at dusk with poor visibility and from more than 150 metres away.
Others say it was a lucky shot or a ricochet.
The finger has also been pointed at anti-treaty leader Eamon de Valera, who was in the area at the time of the ambush.
But the jury is still out on whether the future taoiseach and president knew of the murder plot.
Others believe one of Collins' comrades in the convoy - who had been drinking - shot him by mistake, or carried out the hit as part of a conspiracy by rivals.
Collins was murdered aged 31 while on an inspection tour of Munster and searching for a basis for peace with IRA leaders opposed to the Treaty (Pictured: Collins with his convoy just hours before being ambushed)
Or was it the work of MI6, who wanted to prevent Collins from freeing the rest of the Irish counties, which today make up Northern Ireland?
Rumours have long suggested Denis 'Sonny' O'Neill, a marksman who served in the British Army during World War One, was behind the hit.
Mr O'Neill was part of the anit-treaty IRA and may have had motive - but Mr Cullivan recently unearthed evidence that he had returned from war with a 40% disability to his right arm, undermining his marksmanship.
Mr Cullivan's own documentary,
