Sinn Fein leader Gerry Adams remained in police custody for a second day on Thursday as detectives questioned him over his alleged role in the Irish Republican Army's abduction, killing and secret burial of a Belfast mother-of-10 in 1972.
Senior politicians in Adams' Irish nationalist party said they hoped he would be released soon without charge and accused British authorities of timing Wednesday's arrest to undermine Sinn Fein's campaigning in elections taking place in both parts of Ireland later this month.
Under Northern Ireland's anti-terrorist law Adams can be held until Friday night, by which time police must release or charge him, or seek a judicial extension to his custody.
Adams, 65, has always denied any role in the outlawed IRA, but every credible history of the Sinn Fein-IRA movement has identified him as a senior commander since the early 1970s.
The IRA killed nearly 1,800 people from 1970 to 1997, when it ceased fire to permit Sinn Fein to pursue peace negotiations with Britain and leaders of Northern Ireland's Protestant majority.
Former IRA members interviewed for a Boston College-commissioned research project have linked him to the slaying of Jean McConville, a 38-year-old widow whom the IRA branded a British spy. An investigation by Northern Ireland's Police Ombudsman said there was no evidence that she was an informant.
Northern Ireland police successfully sued in US courts to acquire several tapes of IRA members, and have already used them to charge Adams' alleged former Belfast IRA colleague, 77-year-old Ivor Bell, with aiding McConville's killers.
The IRA did not admit killing her until 1999, and her remains - including a skull bearing a single gunshot wound to the back of the head - were found in 2003 near a Republic of Ireland beach.
Michael McConville, a son of the dead woman, said the children know the names of some of the IRA men who abducted their mother, but "I wouldn't tell the police".
"Me or one of my family members or one of my children would get shot by these people. People think this (IRA threat) has gone away. It hasn't," McConville said.
"Splinter groups of the IRA would class you as an informant and shoot you."