The 65-year-old was arrested last Wednesday by police investigating the abduction and murder of Disappeared victim Jean McConville after he presented himself at Antrim police station.The former West Belfast MP was questioned for four days after police were granted extra time before he was released on Sunday evening pending a report to the PPS.But, writing in the Guardian, Mr Adams has complained that during his period in detention, "no new evidential material, indeed no evidence of any kind, was produced"."My arrest and the very serious attempt to charge me with IRA membership is damaging to the peace process and the political institutions," he commented.He added that over the course of questioning, "it became clear that the objective of the interviews was to get to the point where they could charge me with IRA membership and thereby link me to the McConville case"."The membership charge was clearly their principal goal. The interrogators made no secret of this."The Louth TD added: "I am innocent of any involvement in the abduction, killing or burial of Mrs McConville, or of IRA membership. I have never disassociated myself from the IRA and I never will, but I am not uncritical of IRA actions and particularly the terrible injustice inflicted on Mrs McConville and her family."I very much regret what happened to them and their mother and understand the antipathy they feel towards republicans."Mrs McConville, a 37-year-old widow and mother of 10 children, was abducted in December 1972 from her flat in the Divis area of west Belfast and shot by the IRA.Her body was recovered on a beach in Co Louth in August 2003.One person, 77-year-old veteran republican Ivor Bell, has been charged with aiding and abetting the murder and of IRA membership. Six others including Mr Adams have been released pending a report to the PPS.A PSNI spokesperson said "there is a substantial amount of material to be processed" in Mr Adam's case and it will be forwarded to the PPS "in due course".The decision on whether to proceed with a prosecution now rests with the deputy director of Public Prosecutions Pamela Atchison after it emerged that the Director of Public Prosecutions Barra McGrory QC previously acted as Mr Adams' lawyer.Six of Mrs McConville's children gathered to mark what would have been her 80th birthday on Wednesday and planted a tree in her memory.