Jean McConville's IRA killers tried to silence her son days after she vanished, it has been revealed.

Michael McConville, who was 11 when his mother was snatched from her west Belfast home in 1972, was abducted, beaten and threatened at gunpoint by young republicans intent on keeping her disappearance quiet.

He said: "They tied me to a chair; were hitting me with sticks. They were putting a gun to my head.

"They said they were going to shoot me."

Mrs McConville, a widowed mother-of-10, was among 17 people abducted, killed and secretly buried by republican paramilitaries during the Troubles.

Even though a former IRA boss claimed Gerry Adams ordered her murder, the Sinn Fein president again insisted in a special television documentary that he had nothing to do with the young mother's death.

Brendan "Darkie" Hughes, once a close friend of Mr Adams, said: "There's only one man who gave the order for that woman to be executed. That man is now the head of Sinn Fein."

But, Mr Adams, now a Louth TD, told the documentary makers: "I had no act or part to play in either the abduction, the killing or burial or Jean McConville or indeed any of these other people.

"Brendan is telling lies."

Hughes, who died in 2008, made his claim in an interview with researchers at Boston College seven years earlier. It was given on the condition that nothing would be published until after his death.

Old Bailey bomber Dolours Price, who died earlier this year, also alleged Mr Adams had been her IRA Officer Commanding during the early 1970s and specifically implicated him in the murder of Mrs McConville.

The widow's remains were recovered at Shelling Beach, Co Louth in August 2003 - more than three decades after she was abducted. Forensic tests revealed she had been badly beaten and shot in the back of the head.

The discovery was made by a member of the public and is part of a live police investigation.

"If I lived for 200 years I still don't think I could describe how I felt when we got my mother's body back," said Mr McConville, who wants the killers brought to justice.

"They took my mother from her house. To bring her down to a beach with her hands tied behind her back and to put a gun to the back of her head and shoot her - that's an execution.

"They knew exactly who they were killing and what she was leaving behind. That was a war crime and the people responsible should be brought to The Hague."

Despite the passage of over 40 years Mr McConville, now aged 51 and a father-of-four, can still vividly recall the day his mother was dragged from her home with wailing children clinging desperately to her limbs.

A gang of up to 20 IRA men and women were involved, including two neighbours who knew the children by name.

His three-hour ordeal at the hands of the IRA's youth wing was a warning to stay silent.

"I was going to give the names of the ones who were not wearing masks to the police," he said.

"They said they were going to shoot me if I told anything about any member of the IRA. That they would shoot me or shoot a member of the family."

Before her death Jean McConville was held and interrogated for up to six days in Belfast. Separate teams of IRA volunteers were organised to drive her south of the Irish border; kill her and to dig the grave.

Lies that she had been an informer who revealed the location of a gun or had stashed army transmitters were circulated by the IRA murder gang.

Claims that she had helped an injured British soldier were also spread among the staunchly republican community and her orphans were shunned.

Mr McConville said: "The people round Divis flats didn't want anything to do with us. We were just shunned to the side. Older people and younger people were saying that she had been seen with UDA men on the Shankill Road or had been seen in other places. It was all lies and that went on till about the 80s."

Official records from the time stated that the authorities were aware Jean McConville had been "abducted" and noted that a local priest was unsympathetic and reluctant to help.

Mr McConville said he knew his mother was never coming back when an IRA man called to the family home and handed back her wedding rings and purse.

"Although I was only 11, I knew that my mother was dead. Having seen at first hand the brutality of these people I knew that my mother was killed and that she wouldn't be coming back," he said.

To date the bodies of 10 people - who became known as The Disappeared - have been recovered.

A further seven people including west Belfast IRA man Joe Lynskey, Brendan McGraw from Twinbrook and SAS-trained officer Captain Robert Nairac have never been found.

Gerry Adams, who has always denied being a member of the IRA, said he was committed to helping find those who are missing.

He said: "My focus is in trying to do what I can as an individual to bring those remaining bodies to the families who grieve them and want a burial place to go to.

"All of us bear a responsibility - those of us who are in leadership and I have never shirked that."

The Disappeared, a co-production between the BBC and RTE, will be aired tomorrow night and on BBC Four on Tuesday.

The sister of a teenager abducted, murdered and secretly buried by the IRA has revealed how she is haunted by an image of him standing over his shallow grave.

Dympna Kerr, 60, cannot bring herself to visit the Co Monaghan bog where the body of her younger brother Columba McVeigh is believed to have been hidden in 1975.

Choking back tears she said: "I refused to go because I have an image in my head.

"I have an image in my head of Columba standing there crying, looking into a hole."

Mr McVeigh, 19, from Dungannon, Co Tyrone was one of the 17 people kidnapped, killed and buried by republicans between 1972 and 2003.

His mother Vera, who had vehemently denied IRA allegations that he was an informer, died in May 2007, aged 82 without being reunited with her son.

Mrs Kerr, now a mother of four, said: "It's like someone stabbing you in the heart. To think of what my mum and dad went through for all those years. My dad died not knowing that Columba was dead and, for years, my mother bought birthday presents and Christmas presents for him and put them in the wardrobe to keep in case he came back."

To date, six searches by the independent commission set up under the 1998 Good Friday Agreement peace agreement to help locate victims' remains have proved unsuccessful.

Mrs Kerr said it gets more difficult to cope each time.

"I never done anything to the IRA, neither did my mum, so why are they torturing us - 38 years on and they are still torturing us," she added.

"Every time there is a dig you get up in the morning and think this could be the day that he is found. You get your hopes up and then when they don't find him it is like someone has died all over again.

"It's very hard when you lose someone close to you - I have lost my father, mother and husband. But, you bury them; you grieve for them; and you have a grave to visit so there is a healing process. With Columba there is none of that."

Mrs Kerr, who was two years older than her brother, said she never accepted he had deliberately stayed away.

"I've always said he was dead - from day one when he went missing," she said. "I've always said he was dead. And, why did I say he was dead? Because he needed my mum too much, he couldn't have stayed away. He depended on my mother too much."

She hopes that someone will come forward with fresh information that could lead to the recovery of her brother's body.

"When Columba disappeared in 1975 I didn't have children. And, maybe those who were responsible didn't have any children either. But, now they may have children or grandchildren now and realise the impact that his death has had. I hope that by speaking out it might prick someone's conscience to give us that final piece of information that we need.

"All we want is to put him in the grave in Donaghmore beside my mum and dad. Their identity is of no importance to us. All we want is to take him home. His name is already on the headstone."