Getting evidence from intelligence is a slow process
No matter how good the intelligence flow, there will always be missing pieces.
The police now believe they have identified the bombmaker who constructed the device that killed police constable Ronan Kerr. But that attack, almost three years ago, came in under the radar – there simply wasn't the same flow of intelligence back then.
Converting the information that is now available into evidence will be a painstaking process.
We read in this police briefing how detectives are looking at links to more than a dozen other incidents stretched out over a number of years.
That link is to the group that now calls itself the IRA, a coalition that brought a number of the different parts of that dissident world under the one roof.
When you look at the list of linked incidents under investigation, you see the fine lines between what the dissidents would term success and failure.
What we also see are those moments when MI5 and PSNI Intelligence have had information, and those other occasions when they have been in the dark.
The under-car bomb that seriously injured police constable Peadar Heffron was another moment when they didn't see or hear the planning for that attack.
The dissidents know there have been many occasions when they have been seen and heard – picked up in patient surveillance operations or 'betrayed' by talking inside their own ranks.
The new IRA coalition was about tightening up internal security, bringing weapons and expertise under one leadership, but still they struggle to put together a series of attacks.
For every shooting or bombing that succeeds in their terms, many others fail.
And the leadership of this organisation has been disrupted.
Those who hold the highest rank within the dissidents are known not just to those in the corridors of security and intelligence gathering, but also across the republican communities.
Their names are no secret – more an open book.
Even so, the threat posed by this IRA coalition and the other factions such as the Continuity IRA and Oglaigh na hEireann (ONH) cannot be taken lightly.
Indeed, it was the last of those groups that put its name to the bomb placed under Peadar Heffron's car, telling this newspaper in an interview: "We target the uniform and what it stands for."
It is known that some of those identified at the time with the ONH faction and that attack have since become key figures in the leadership of the IRA coalition.
That is how this world, and those who are part of it, move from one place and one title to another.
We know from watching the pattern of activity that much of what they attempt fails, but not all of it, and that deadly war play continues in the background.