I think that the Church, the British government and the RUC found themselves faced with the same incredibly difficult decision to make.
Even though I was only barely in my teens in 1972, I remember the horror of the Claudy car bombings very well. Three car bombs detonated in a village busy with innocent civilians shopping and going about their daily business. There was no warning: apparently all the phone lines had been damaged in an earlier bombing. I also remember that very shortly afterwards - within a few months - it was strongly suspected not just by the RUC but by nationalist politicians, that a [named] priest, possibly three priests, were involved. In the circumstances of Northern Ireland in the 1970s, had a priest been arrested even on suspicion of such a crime, it would have been open season on every Catholic priest in Northern Ireland. It doesn´t require much imagination to figure out what would have happened then.
So, as this report states, the police approached the Church authorities to discuss the situation and the decision was not to arrest Fr Chesney but to remove the priest to a parish across the border in the Republic. The Church authorities did question Fr Chesney at the time and he vigorously denied involvement, and yes, the police were free to arrest him on any of the several occasions he crossed the border. But had they done so at any time during the 1970s (Fr Chesney died in 1980), the same consequences would have ensued.
Did they make the right decision? Or would it have been better to arrest the priest, try to contain the fallout, and at least give him the opportunity to clear his name?
What we have now is that this report finds that there was evidence that Fr Chesney was quartermaster for the IRA in the area, and he is not around to defend himself. Nearly forty years later, the relatives of the victims still don´t know what really happened or who was responsible for the murder of their family members and they, rightly, want a full, public enquiry into the bombing. And, in hindsight, the Church (whatever good intentions it and the police had about trying to prevent a bloodbath) looks like it colluded in a cover up.