Sinn Fein leader Gerry Adams continued to be questioned about the murder of a Belfast mother-of-10 in police custody tonight as one of her sons revealed he was too scared to tell detectives who he believed was responsible.
As the 65-year-old politician was quizzed about the notorious IRA killing of Jean McConville - a crime he denies any role in - Michael McConville spoke of his fears of making a statement to the police in case he or other family members were shot by republican extremists for informing.
"The IRA robbed a family of their mother growing old, they took everything away from us," he said.
Mr McConville said he recognised local faces when an IRA gang arrived to drag his mother away screaming in terror from their home in the Divis flats in west Belfast in 1972.
But he added: "Everybody thinks that the IRA has gone away but they have not. If we tell we will be shot."
His mother was abducted, shot and then secretly buried - so becoming one of the "Disappeared" victims of the Troubles. Her body was not found until 2003 on a beach in Co Louth.
Mr Adams was arrested at Antrim police station last night after voluntarily presenting himself for interview and spent the night in custody. Questioning resumed this morning and continued through the day.
The former West Belfast MP and current representative for Co Louth in the Irish Dail can be held for up to 48 hours without charge, with officers having an option to apply to a judge for that detention period to be extended if they think it is required.
Mr Adams's long standing party colleague and friend, Stormont Deputy First Minister Martin McGuinness, claimed the arrest was aimed at inflicting political damage on Sinn Fein in the mouth of an election and said it was an example of the "dark side" of policing trying to flex its muscles.
"I view his arrest as a deliberate attempt to influence the outcome of the elections that are due to take place in three weeks' time, north and south on this island," he said.
"That raises very serious questions around why that is the case and what is the agenda."
But Prime Minister David Cameron rejected any suggestion the arrest was politically motivated.
"There has been absolutely no political interference in this issue," he said.
He added: "We have an independent judicial system, both here in England and also we do have one in Northern Ireland.
"We have independent policing authorities, independent prosecuting authorities. Those are vital parts of the free country and the free society we enjoy today."
Police Service of Northern Ireland Chief Constable Matt Baggott declined to be drawn into detailed comment on the arrest at a meeting of his oversight body, the Northern Ireland Policing Board, in Belfast.
However, he said the investigation would be "effective, objective and methodical".
Asked about the McConville probe in the context of the legacy of Northern Ireland's troubled past, Mr Baggott said: "Effective investigation applies to any unsolved matter and it would be inappropriate for me to comment on any individual investigation other than to say they will be objective and methodical."
Stormont's Democratic Unionist First Minister Peter Robinson earlier addressed the perceived threat to Mr McConville
"We have had a lot of words from Sinn Fein about how wrong what happened to Mrs McConville was," he said.
"Here is an opportunity. This is the same republican movement of which they are a part, that the people who carried out this act were a part.
"Let them meet Michael McConville, let Michael McConville impart to them the names of those who were involved.
"I challenge Sinn Fein that they should do their civic duty and responsibility of handing over those names to the PSNI."
Mr Adams has rejected allegations by former republican colleagues that he had a role in ordering the death of Mrs McConville - who was wrongly accused of passing information to the British Army in Belfast.
No one has ever been charged with the murder of the 37-year-old widow, but after years without progress in the criminal investigation there have been a series of arrests in recent weeks.
A veteran republican - 77-year-old Ivor Bell - was charged in March with aiding and abetting the murder. Five other people have been detained and questioned.
The recent police activity followed a decision by a US court compelling a Boston university to hand over to the PSNI recorded interviews with republicans about Mrs McConville's murder.
Boston College interviewed a number of former paramilitaries about the Troubles on the understanding transcripts would not be published until after their deaths - but that undertaking was rendered ineffective when the court last year ordered that tapes that contained claims about the killing be given to detectives.
Mr Adams has always denied IRA membership or any role in Mrs McConville's death and said in March he would be available to meet detectives if they wished to speak with him.
He presented himself at the police station by prior arrangement and issued a statement through his party minutes after the PSNI announced an arrest had been made.
''While I have concerns about the timing, I am voluntarily meeting with the PSNI this evening,'' he said last night, questioning why police chose to interview him in the run-up to an election.
''As a republican leader I have never shirked my responsibility to build the peace. This includes dealing with the difficult issue of victims and their families. Insofar as it is possible I have worked to bring closure to victims and their families who have contacted me. Even though they may not agree, this includes the family of Jean McConville.
''I believe that the killing of Jean McConville and the secret burial of her body was wrong and a grievous injustice to her and her family.
''Well publicised, malicious allegations have been made against me. I reject these.
''While I have never disassociated myself from the IRA and I never will, I am innocent of any part in the abduction, killing or burial of Mrs McConville.''
She was abducted by a gang of up to 12 men and women after being accused of passing information to the British Army in the city.
An investigation later carried out by the Northern Ireland Police Ombudsman rejected the claims that she was an informer.
She was shot in the back of the head and buried 50 miles from her home.
Clearly embarrassed by the killing, the IRA did not officially admit responsibility for the murder until 1999 when information was passed to police in the Irish Republic.
It was not until August 2003 that her remains were found on Shelling Hill beach, Co Louth.
Mr McGuinness insisted Mr Adams could have been questioned without being arrested.
He said the questioning centred on books Mr Adams had written and what others said about him - those "maliciously and vehemently" hostile to the peace process.
The Deputy First Minister claimed: "People who could be described as former republicans (are) targeting the Sinn Fein peace strategy and targeting the leader of Sinn Fein, Gerry Adams.
"It has been disappointing to see the efforts of some of those people together in consort with the dark side within policing."
He drew a contrast between "reformers" within the police service, whom he supported, and those from the "dark side" responsible for the arrest of his friend Mr Adams.
"For over 20 years we have worked very, very closely in developing the peace process, bringing about the political and security transformation that the public enjoy today and, in my opinion, in the course of supporting the peace process, he has been the single most influential figure in the process," he said.
The PSNI tonight issued a further statement on the back of Mr Baggott's comments at the Policing Board.
A PSNI spokesman said: "Today at the Policing Board the Chief Constable emphasised that the police will conduct a thorough and professional investigation into the murder of Jean McConville.
"This will be subject to the full rigours of scrutiny provided in the criminal justice system. Police have a duty to impartially investigate serious crime including murder.
"It is the police's duty to make relevant enquiries, interview those with information, arrest and question suspects and, in consultation with the PPS (Public Prosecution Service), to either charge or submit a file to the PPS in relation to the investigation. This procedure is being followed in this case.
"As one individual has been charged with serious offences and files are being prepared in relation to other individuals, it would be inappropriate to comment further other than to reiterate the Police Service's commitment to treat everyone equally before the law."
Mr McGuinness said later he had spoken on the phone to Mr Cameron to challenge him on the issues of state killings.
He claimed mass killings attributed to the security forces, such as the Army shootings of civilians on Bloody Sunday in Londonderry in 1972 and in Ballymurphy in west Belfast six months earlier, had not been investigated as rigorously as other incidents. Earlier this week the Government ruled out an inquiry into the 11 deaths in Ballymurphy in August 1971.
"The PSNI is duty-bound to fully and energetically pursue all and every investigation and I support and encourage them to do so," said Mr McGuinness.
"But I know that some investigations are pursued more vigorously than others.
"I told the British Prime Minister David Cameron that in a phone call earlier tonight."
He added: "Only this week the British Government told the Ballymurphy families there would be no review of those murders.
"No reinvestigation, no arrests, no compassion for their loss or grief and certainly no political consistency from the British state.
"British forces are protected and immune."