The sole survivor of the Kingsmill massacre has said he has "lost confidence" in the inquest process.
Alan Black and relatives of the ten Protestant men who were shot dead in their work van near the Co Armagh village in 1976 walked out of the inquest today.
The walk-out was in protest over the refusal to name two IRA men suspected of involvement in the murders.
The BBC reports that during the inquest today Coroner Brian Sherrard said naming the individuals was a "complicated" matter and said he would consider the arguments.
Mr Black was the only man to survive the massacre. He was shot 18 times in the hail of bullets that killed his work colleagues.
No one has ever been convicted over the murders.
Mr Black told the Belfast Telegraph: "We were promised back in the day openness and transparency. It has become just the opposite. I am sick about it."
Mr Black criticised the delays in the process and talked of the toll the process is having on the victims' relatives.
"I have not walked away, I am still hoping that someone that was well placed back in the day will come forward as a whistleblower and blow this thing wide open."
"But I have no confidence in the process."
Mr Black expressed frustration that one suspect's name, which he says is known "all over Ireland", has not been named in court.
"We have just had enough. I am sick to the pit of my stomach," he said.
"I have a great loyalty to the boys that died and a great loyalty to their families that were left behind and to see some of them aged people in tears, it is just not fair."
The next inquest hearing is scheduled for the week beginning March 23 but Mr Black is not sure if he will attend.
"I don't know if I will go or not," he said.
"It has knocked the heart out of me. It is brave words I put up outside the court that I was not giving up, but there is no chance of us getting the truth."
Mr Black appealed to anyone who has any information about the murders to contact his legal team.
The ten workman were shot dead on January 5 1976 after gunmen stopped their van and asked who among them was a Catholic, and instructed that man to leave the scene.
DUP MLA William Irwin said the search for justice for the families "must go on".
He said: “I will continue to support the families in any way possible and we must always explore any avenue available to secure justice for those who were so brutally murdered.
"Many had hoped the inquest may have proved to be more fruitful in that process and it is disappointing that the families appear now to have lost confidence in that process.
"We must look at how this disappointing situation has arisen and stand with those families as they continue in their long-standing search for justice.”