Belfast, Northern Ireland (CNN) -- Police on Wednesday arrested Sinn Fein leader Gerry Adams for questioning in connection with the 1972 Irish Republican Army abduction and slaying of a widow, a move that could shake Northern Ireland's fragile peace.
In a statement released shortly before he surrendered for questioning, the 65-year-old Adams vehemently denied any involvement in the killing of Jean McConville. The Police Service of Northern Ireland announced the arrest of a 65-year-old man whom they declined to identify but described as a suspect in the McConville case.
Adams has long denied having any role in the death of McConville, a widowed mother of 10 who was reportedly killed by the IRA because the group believed she was a spy for the British army.
"I believe that the killing of Jean McConville and the secret burial of her body was wrong and a grievous injustice," Adams said in the statement posted on his party website. "Malicious allegations have been made against me. I reject these."
The questioning of Adams was not unexpected. Adams said he told authorities last month that he was willing to meet with investigators.
Long associated with the IRA, once considered the armed wing of Sinn Fein, Adams is a prominent Catholic politician who helped broker peace in Northern Ireland. Today, Sinn Fein is Ireland's second-largest opposition party.
"While I have never disassociated myself from the IRA and I never will, I am innocent in the abduction, killing or burial of Mrs. McConville," Adams said.
Northern Ireland is part of the UK, and Protestant fighters wanted to keep it that way. Catholics were fighting to force the British out and reunify the north with the rest of Ireland.
Known as the Troubles, the conflict lasted 30 years, ending in 1998 with the Good Friday Agreement that brokered peace. The agreement provided a political framework for power-sharing among the parties.
The IRA admitted in 1999 to killing a number of people who have become known as "The Disappeared" -- those who vanished during the Troubles.
Among the victims was McConville, whose remains were found partially buried on a beach in County Louth in 2003. She died of a single gunshot wound to the back of the head.
McConville, 38, was taken from her home in Belfast in December 1972, her daughter, Helen McKendry, told CNN in 2012.
"They came about tea time and they dragged her out of the bathroom and dragged her out," said McKendry, who was a teenager at the time. "...All I ever wanted was to know the reason why they killed my mother."
The investigation into McConville's killing was revived by authorities after the release of interviews given by members of the IRA, who implicated Adams.
The recordings were made by Boston College as part of the Belfast Project, which is a collection of interviews conducted with former Northern Irish paramilitary fighters. They provide an oral history of the decades of fighting.
Participants in the project believed their recorded interviews would be kept secret until their deaths.
One of those featured was Brendan Hughes, a now-deceased former commander of the IRA, a Catholic paramilitary.
Hughes told his interviewer about McConville: "I knew she was being executed. I knew that. I didn't know she was going to be buried or disappeared as they call them now."
Hughes went on to allege Adams was involved: "The special squad was brought into the operation then, called The Unknowns. You know when anyone needed to be taken away, they normally done it. I had no control over this squad. Gerry had control over this particular squad."
Adams has called the allegations libelous.
Peter Taggart reported from Belfast, and Chelsea J. Carter reported and wrote from Atlanta. CNN's Greg Botelho and Nic Robertson contributed to this report.