The son of Jean McConville has welcomed the arrest of Gerry Adams and said he hopes it marks a step towards his family's 40-year search for justice.
Mr Adams was interviewed by detectives at Antrim Serious Crime suite yesterday over the disappearance and murder of the west Belfast mother-of-10.
Mrs McConville was abducted in December 1972 in front of her children before being shot in the head and secretly buried.
Her remains were not found until 2003 when a walker on a beach in Co Louth came across them.
Michael McConville told the Belfast Telegraph last night that he welcomed the arrest of Mr Adams.
"The McConville family is glad to see that the police is taking our mother's murder seriously and is doing all they can to bring the people that murdered her to justice," he said.
"I would say an awful lot of people in the north and south of Ireland are glad to see Gerry Adams being arrested for this."
However, Sinn Fein blasted the timing of the PSNI's questioning of the Louth TD as "politically motivated".
The republican party played down the incident, claiming that Mr Adams met detectives voluntarily.
Mr Adams again denied any involvement in the disappearance and murder of Mrs McConville, and claimed he has worked to help her family.
"As a republican leader I have never shirked my responsibility to build the peace," he said.
"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."
Mr Adams said the murder of Mrs McConville and 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," he said.
"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."
Sinn Fein vice-president Mary Lou McDonald claimed the timing of the police decision was designed to damage her party and Mr Adams.
"There has been a concerted and malicious effort to link Gerry Adams to this case for some considerable time," she said.
"He has consistently and forthrightly rejected any suggestion that he had any part in what happened to Jean McConville 42 years ago or that he has any information about these dreadful events.
"I believe the timing of this latest decision by the PSNI is politically motivated and designed to damage Gerry Adams and Sinn Fein."
The arrest comes after the PSNI seized taped interviews with several IRA veterans, including Brendan Hughes and Dolours Price, which were made as part of a Boston College project. The tapes are believed to include allegations that Mr Adams ordered the killing of Mrs McConville.
Former republican prisoner Anthony McIntyre, who carried out many of the interviews, said Sinn Fein were "in a bind" due to its support for the PSNI.
He said he was opposed to any arrests over the past.
"I don't see what it has to offer," he told the Belfast Telegraph.
"Sinn Fein are in a bit of a bind because they support the PSNI while the PSNI are arresting their leader.
"But to me the irony of it is Adams from Ballymurphy is arrested the day after the British refuse an inquiry into the mass murder by paratroopers of civilians in Ballymurphy.
"It's got politics written all over it. It seems to be the British way of rubbing the nationalist narrative into the dirt."