BELFAST, Northern Ireland -- Northern Ireland police are casting a wider net in their efforts to prove Sinn Fein leader Gerry Adams once commanded the outlawed Irish Republican Army and ordered the 1972 killing of a Belfast mother of 10, according to party colleagues and retired militants.
Details of an expanding trawl for evidence emerged Saturday as detectives spent a fourth day questioning Mr. Adams about the IRA's abduction, killing and secret burial of Jean McConville 42 years ago -- an investigation that has infuriated his IRA-linked party.
Mr. Adams had been scheduled to be charged or released by Friday night, but a judge granted police a 48-hour extension of his detention. Mr. Adams, 65, took part in the court hearing via a video link from the police interrogation center west of Belfast.
Sinn Fein's deputy leader, Martin McGuinness, said he had been told by Mr. Adams' legal team that detectives were questioning him about many of his speeches, writings and public appearances going back to the 1970s, when he was interned without trial as an IRA suspect and wrote a newspaper column from prison using the pen name "Brownie."
Mr. McGuinness, a former IRA commander who today is the senior Catholic in Northern Ireland's unity government, told a street rally in Catholic west Belfast that police would fail to prove IRA membership claims against Mr. Adams, as last happened in 1978, when Mr. Adams was arrested in the wake of a hotel firebomb that burned 12 Protestants to death.
"That case was based on hearsay, gossip and newspaper articles. It failed then, and it will fail now," Mr. McGuinness said in front of a newly painted mural of a smiling Mr. Adams beside the words, "Peacemaker Leader Visionary."
Aides to Mr. Adams and Mr. McGuinness said Catholic west Belfast residents with IRA affiliations had been approached by police recently, asking them to make statements about their knowledge of Mr. Adams' IRA activities.
And 200 miles to the south, in the Republic of Ireland, an IRA veteran who served 31 years in prison for murdering a policeman said a Northern Ireland detective knocked on his door seeking a witness statement. Peter Rogers, 69, said he refused.
Last month, Mr. Rogers told the BBC he met both Mr. Adams and Mr. McGuinness in Dublin in 1980 to discuss their plans to smuggle stolen mining explosives from the Irish Republic to England for use in the IRA's bombing campaign on London. Mr. Rogers said Mr. Adams was annoyed because he had failed to deliver them by ferry across the Irish Sea.
Mr. Rogers said he told Mr. Adams and Mr. McGuinness that the explosives were unstable and could detonate while being transported. He said Mr. Adams rejected his concerns.
"Gerry said: 'Look Peter, we can't replace that explosive. You will have to go with what you have, and as soon as you can get it across, the better' ... I was given a direct order," Mr. Rogers told the BBC.
Before his Wednesday arrest, Mr. Adams rejected Mr. Rogers' claims as false.