Both sets of protagonists, in reality, are on the side of the angels. Or to be more precise, of "truth". And yet both are irreconcilable. The arguments about the Boston College tapes and the evidence they may contain about those involved in the murder of Jean McConville and others are ultimately about which truth shoudl prevail, that which the families of the bereaved cry out for and deserve, or the truth of an as-comprehensive-as-possible historical record. And there is no easy, comfortable answer, not least because the tapes are also just one truth whose accuracy depends on comparison with multiple other truths.

Blame and recriminations between the college and the two researchers who made the tapes, Ed Moloney and Anthony McIntyre, about the nature of guarantees to sources each claims were given unfortunately cloud the real issue. Like it or not, the release to the PSNI of parts of 11 tapes, whether or not convictions ensue, will have a deeply chilling on first-hand research by oral historians on the real story of the Troubles. Academics are already speaking of this well running dry.

The decision by Boston College now to return the tapes to those who gave testimony will have the same effect of obliterating the record. Little wonder Sinn Féin is delighted.

It is in the nature of the events, specifically the context of an underground war, that an historical record can not be pieced together in any other way than by assuring former– and even current – participants that their testimony will remain sealed for a generation. As journalists know only too well, unless sources are protected, and know that they can trust those who make promises to do so, they will dry up.

In response to the conviction that the tapes could produce results in one case, an immediate and understandable consolation for one family, a single golden egg, the PSNI has killed the goose.