The ghost of Jean McConville has haunted Gerry Adams throughout the peace process.
The murder of Mrs McConville – abducted, shot in the back of the head and secretly buried – refuses to go away.
The fact that she was a mother-of-10 and a widow, and the brutal nature of her death, means the 1972 murder has buried itself deep in the public consciousness.
While Mr Adams has always denied involvement in the McConville murder or of being in the IRA, a succession of republicans have said different in recent years.
The most prominent of the 17 victims 'disappeared' by the IRA, 37-year-old Jean McConville was a widow when she was dragged from her Divis flats home by an IRA gang of up to 12 men and women in front of her children.
They had accused her of being an informer, although an investigation later carried out by the Police Ombudsman rejected the claims.
Her remains were finally found at Shelling Hill beach in Co Louth in the Republic in August 2003.
Mr Adams is the latest republican to be arrested over Mrs McConville's murder.
One was Alex Murphy (56), who was previously sentenced to life imprisonment for the murder of two Army corporals in 1988.
Only last month, Evelyn Gilroy, an ex-internee from west Belfast, expressed her anger that "low-level republicans" had been arrested about the murder while police hadn't even questioned the Sinn Fein president.
"Police have lifted people who were 15 and 16 at the time of the killing, yet Gerry Adams remains untouched," she said.
"The police should stop chasing those who were never in a position in the republican movement to order Jean McConville's execution and instead arrest the only person who was in that position – Gerry Adams."
In March, veteran republican Ivor Bell (77) was charged with aiding and abetting the murder. Detectives later questioned five women and a man about the killing.
Bell denied any involvement in the murder.
Police moved against him on the basis of an interview he allegedly gave to researchers Boston College, Massachusetts.
Shortly after Mr Bell's arrest, Mr Adams asked a lawyer to contact police to establish if detectives want to speak to him about the murder of Mrs McConville. At the time, he dismissed it as "media speculation" that the PSNI wanted to speak to him. He said: "What happened to Jean McConville was a terrible injustice. I was not involved in any part of it.
"If the PSNI wish to talk to me on this matter I am available to meet them. I have asked my solicitor to contact them."
Last year a US court ordered many of the Boston tapes to be handed over to the PSNI after a long legal battle to keep them out of the police's hands.
The PSNI used an international treaty between Britain and the US to access the recordings held at Boston College relating to the McConville killing.
The researchers – former IRA prisoner Anthony McIntyre and and journalist Ed Moloney –had promised republicans who were interviewed that their recordings would not be made public until after their deaths.
In one interview, former Belfast Brigade commander, Brendan Hughes, who died in February 2008, said Mr Adams had ordered the widowed mother's execution.
But Mr Adams caused outrage when he accused Hughes, who was highly regarded in the republican community, of lying.
The former West Belfast MP denied similar accusations levelled by the late Dolours Price. She was one of Mrs McConville's abductors, and claimed to have carried out the action on Adams' order.
Again, Mr Adams sought to discredit a former IRA member, blaming the deteriorating mental health that preceded Ms Price's death.