Since they haven't been able to find evidence of who actually killed Rosemary Nelson it's not exactly surprising they haven't been able to find evidence of any actions carried out by state authorities to bring this about.

I note they leave open the suggestion that people working within the relevant agencies might have been involved - "...a rogue member or members..."

I believe the term "deniability" is often used in relation to such things.

This was a dirty war, and dirty things get done in dirty wars. By all sides.