The Chief Constable of the PSNI has said criticism of his force's arrest of Gerry Adams last week was unfair.

Matt Baggott said Sinn Féin's claim that there was a "dark side" to the PSNI was untrue.

He said questioning the motivation or impartiality of police officers tasked with investigating serious crime in this very public, generalised and vague manner was both unfair and inappropriate.

Mr Adams was arrested last week by police investigating the abduction and murder of Jean McConville.

Meanwhile, Boston College, which is storing an oral history of Northern Ireland's Troubles, has said it is willing to hand back tapes of interviews.

The PSNI last year won a legal battle to force the college to hand over sections of the archive that related to the abduction and murder of Mrs McConville in 1972.

Following Mr Adams's release from custody after four days of questioning, he said most of the evidence detectives presented to him was based on allegations given by interviewees to the project.

In a statement this morning, Mr Adams said the project was flawed from the beginning.

He said: "It was conceived by Lord Paul Bew. He proposed Ed Moloney and Anthony McIntyre despite the fact that both individuals were extremely hostile to myself, Sinn Féin, the peace process and the political process."

Former IRA members Brendan Hughes and Dolours Price, both now deceased, claimed in the tapes that Mr Adams had a role in ordering the murder of Mrs McConville.

The 40-plus participants in the oral project had been assured that their accounts would not be made public until their deaths, but that undertaking was undermined by the US court ruling.

Of more than 80 interviews contained in the archive, the court decision saw police obtain sections of 11 tapes.

Amid concerns about the status of the remaining interviews, the college has now indicated its willingness to hand back the tapes to those who were interviewed.

Mr Adams said: "I welcome the end of the Boston College Project, indicated by the college's offer to now return the interviews to the interviewees before the securocrats who cannot live with the peace seek the rest of the archive and do mischief."

Meanwhile, Northern Ireland Deputy First Minister Martin McGuinness said he believes there would be no Good Friday Agreement if key negotiators knew 16 years ago that they would be arrested.

He said he believed the arrest of Mr Adams was more about trying to pin an IRA membership charge on him than investigating the murder of Mrs McConville.

He also accused Taoiseach Enda Kenny of being out of touch and careless in relation to his handling of the situation.

Mr Adams also criticised Mr Kenny's reaction to the issue as he spoke at an election rally in Dublin tonight.

Mrs McConville was dragged away from her children in the Divis flats in west Belfast by a gang of up to 12 men and women after being accused of informing to the security forces.

She was interrogated, shot in the back of the head and then secretly buried, becoming one of the "Disappeared" victims of the Troubles.

Her body was found on a beach in Co Louth in 2003, 80km from her home.