A teenager injured during a sectarian IRA massacre cried for his mother as he lay waiting to die, the sole survivor has told the Kingsmill inquest.
A gunman stood over him and shot him in the face, blowing his head off, Alan Black said.
A new inquest is being held into the republican killing of 10 Protestant workmen at a Co Armagh roadside 40 years ago.
Mr Black said: “Robert Chambers - my last memory was him lying on the ground calling for his mother.
“He was only wounded at that time. The gunman came over and shot him in the face... His head was blown off.”
A new inquest into the January 1976 murder was ordered by Northern Ireland Attorney General John Larkin QC.
Mr Black told the hearing at Belfast Coroner’s Court that the water from the rain running down the road splashed in his face as he lay badly injured.
“I felt the most unbelievable level of pain, as if someone was sticking hot needles into my whole body.”
He said people were “screaming in pain”.
“They shot John McConville through the head.
“I knew my mates were dead because there was no more moaning.”
Mr Black said he saw the gunmen’s Doc Marten shoes and the tips of their rifles as they stood over him.
Then the shooting became more “measured” and heads exploded.
The textile factory workers were ambushed as they travelled along the Whitecross to Bessbrook road in rural south Armagh on January 5 1976 - one of the darkest years of the Troubles - allegedly in reprisal for earlier loyalist killings.
Father-of-three Mr Black was shot several times.
The men’s minibus was stopped and those on board were asked their religion by the gunmen. The only Catholic was told to go.
The gunmen, who were hidden in the hedges, ordered the rest to line up outside the van and then opened fire.
The 10 who died were John Bryans, Robert Chambers, Reginald Chapman, Walter Chapman, Robert Freeburn, Joseph Lemmon, John McConville, James McWhirter, Robert Samuel Walker and Kenneth Worton.