Grab, I don't think there is any chance of most of the murderers doing time in prison. That was part of the deal to get a ceasefire.
However, I think it is important that the truth be revealed. It is quite clear to anyone, that the Provisional IRA, INLA, IPLO, UVF, UFF etc. etc. acted illegally.
The question is, to what extent, and at level of seniority, were members of state organisations (UK or RoI), [whose job was to maintain law & order] complicit.

Frankly, given the polarisation that occurred, it was always likely that some members of the police/military would turn a blind eye to certain things done by "their own side". The "few bad apples" scenario.

However, if senior police/army officers, senior civil servants, or even government ministers, who were supposed to uphold the law, were involved in politically motivated murders, the public has a right to know.