Soldiers from an undercover unit used by the British army in Northern Ireland killed unarmed civilians, former members have told BBC One's Panorama.
Speaking publicly for the first time, the ex-members of the Military Reaction Force (MRF), which was disbanded in 1973, said they had been tasked with "hunting down" IRA members in Belfast.
The details have emerged a day after Northern Ireland's attorney general, John Larkin, suggested ending any prosecutions over Troubles-related killings that took place before the signing of the Good Friday Agreement in 1998.
The proposal has been criticised by groups representing relatives of victims.
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.
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.
He described their mission as "to draw out the IRA and to minimise their activities... if they needed shooting, they'd be shot".
Another former member of the unit said: "We never wore uniform - very few people knew what rank anyone was anyway.
"We were hunting down hardcore baby-killers, terrorists, people that would kill you without even thinking about it."
A third former MRF soldier said: "If you had a player who was a well-known shooter who carried out quite a lot of assassinations... then he had to be taken out.
In 1972 there were more than 10,600 shootings in Northern Ireland. It is not possible to say how many the unit was involved in.
The MRF's operational records have been destroyed and its former members refused to incriminate themselves or their comrades in specific incidents when interviewed by Panorama.
When asked if on occasion the MRF would make an assumption that someone had a weapon, even if they could not see one, one of the former soldiers replied "occasionally".
"We didn't go around town blasting, shooting all over the place like you see on the TV, we were going down there and finding, looking for our targets, finding them and taking them down," he said.
"We may not have seen a weapon, but there more than likely would have been weapons there in a vigilante patrol."
The Ministry of Defence refused to say whether soldiers involved in specific shootings had been members of the MRF.
It said it had referred allegations that MRF soldiers shot unarmed men to police in Northern Ireland.
But the members of the MRF who Panorama interviewed said their actions had ultimately helped bring about the IRA's decision to lay down arms.
Gen Sir Mike Jackson, the former head of the British army, and a young paratrooper captain in 1972, said he had known little of the unit's activities at the time, but admired the bravery of soldiers involved in undercover work.
He said: "That takes a lot of courage and it's a cold courage. It's not the courage of hot blood [used by] soldiers in a firefight.
"You know if you are discovered, a pretty gruesome fate may well await you - torture followed by murder."
Panorama has learnt a Ministry of Defence review concluded the MRF had "no provision for detailed command and control".
Forty years later and families and victims are still looking for answers as to who carried out shootings.
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.