Brian Rowan former BBC Security Correspondent explores the maverick Republican theory (subs needed):
Inside the republican community there were many who wished Denis Donaldson dead.
As news of the shooting broke at teatime on Tuesday, one source remarked: “There would be no shortage of people prepared to shoot him.” Indeed, in the words of this source, they would have been “queuing up to do it”.
But asked was it the IRA? he replied “definitely not”. Others would not be so definite. It is a time for open minds – a time to wait for more pieces of the jigsaw and for the picture to become clearer.