Anyone actively involved in shooting unarmed civilians during the Troubles must be prosecuted, Northern Ireland's former deputy first minister has said.
Seamus Mallon's comments came after ex-soldiers told BBC One's Panorama that a secret unit used by the British Army in the early 1970s shot unarmed civilians.
Northern Ireland Attorney General John Larkin has suggested prosecutions for Troubles-related killings should end.
Ex-members of the Military Reaction Force (MRF), which was disbanded in 1973, told Panorama they had been tasked with "hunting down" IRA members in Belfast, saying their unit had helped save many lives.
Mr Mallon, who became deputy leader of the nationalist SDLP party and was one of the architects of the Good Friday Agreement, told BBC Radio 4's The World at One that those involved must be held accountable, even 40 years later.
For 15 years, Northern Ireland has been divided about how to deal with the legacy of three decades of conflict.
The compromise has been the establishment of the Historical Enquiries Team, a group of former detectives, who are reviewing all deaths in Northern Ireland during the conflict, primarily to answer questions from their relatives.
But now the Northern Ireland attorney general has reignited the vexed issue of whether truth recovery through a virtual amnesty is preferable to prosecution.
John Larkin has called for an end to all prosecutions and inquiries in relation to Troubles-related killings.
The closest former MRF soldiers have previously come to breaking cover is as the pseudonymous authors of two semi-fictionalised paperbacks, one of whom has referred to the MRF as a "legalised death squad".
The factual account of the MRF may not be quite as colourful. Nonetheless, the evidence gleaned from seven former members, declassified files and witnesses, does point to a central truth - that MRF tactics did sometimes mirror the IRA's.
"If you don't bring these prosecutions and if you don't try to ensure that the law is there for everyone to answer, then you're actually negating the whole thesis of law within society and that is, I'm afraid, what has been happening in instances such as this."
The details of the killings emerged a day after Mr Larkin made his suggestion that any prosecutions over Troubles-related killings that took place before the signing of the Good Friday Agreement in 1998 should be ended.
That proposal has been criticised by groups representing relatives of victims and by Northern Ireland's First Minister, Peter Robinson, who said it would allow people "to get away with murder".
Panorama has been told the MRF consisted of about 40 men handpicked from across the British army.
Before it was disbanded 40 years ago, after 18 months, plain-clothes soldiers carried out round-the-clock patrols of west Belfast - the heartland of the IRA - in unmarked cars.
Three former members of the unit, who agreed to be interviewed on condition their identities were disguised, said they had posed as Belfast City Council road sweepers, dustmen and even "meths drinkers", carrying out surveillance from street gutters.
He described their mission as "to draw out the IRA and to minimise their activities... if they needed shooting, they'd be shot".
The soldiers interviewed by Panorama defended their actions, saying they had ultimately helped bring about the IRA's decision to lay down arms.
But The Ministry of Defence said it had referred the disclosures to police.
Panorama has identified 10 unarmed civilians shot by the MRF, according to witnesses.
Mr Mallon said: "You had killings for which there was no logic. This type of incident where people were shot from a passing car, almost as if for fun.
"But was very clear that there was a strategy behind it and I think the huge question to be asked here is who ultimately authorised it, because it had to be authorised both in operational terms by a senior army figure and in political terms by a senior politician."
Former detectives are reviewing all of the deaths in Northern Ireland during the conflict as part of the Historical Enquiries Team set up following the peace process.
Around 11% of the 3,260 deaths being reviewed were the responsibility of the state.
Panorama: Britain's Secret Terror Force, BBC One, Thursday 21 November at 21:00 GMT and then available in the UK on the BBC iPlayer.