Northern Ireland police say they will sue to obtain all of the audiotaped interviews of former militants who described their wartime careers to a Boston College oral history project.

Police last year successfully sued to obtain 11 interviews of Irish Republican Army veterans discussing the 1972 killing of a Belfast mother of 10. Those tapes were used as a basis for arresting Sinn Fein leader Gerry Adams, who was accused by IRA interviewees of ordering the slaying. Adams was released without charge May 4.

Police say in a Thursday statement they now want the entire audio archive. Dozens of IRA veterans and Protestant militants agreed to speak to Boston College researchers on condition their interviews be kept secret until their deaths.

NBC News this week filed a lawsuit seeking access.