‘Sergeant Harvey spoke to a British Army captain up at 321 EOD,’ Bill went on. ‘It seems like British intelligence had always suspected that the three bombs they found in the North were made by an IRA bomb expert from Cork, or thereabouts. They identified him as a market gardener by the name of James MacGreevy, but they could never find watertight proof that he was their man. MacGreevy was questioned by the Garda Special Detective Unit but he flatly denied having anything to do with the IRA and they could find no evidence on his property that he’d been making bombs, so they had to leave it at that.’

Bill was silent for a few moments, with his hands clasped together, as if he were a priest about to give a benediction.

‘You said you found four signatures,’ said Katie. ‘That’s only three.’

‘The fourth could be the clincher, even though the SDU ignored it when they went to interview MacGreevy. They could find no trace of explosives even though they had a sniffer dog with them, because you know that Semtex smells of nothing at all to humans – only to dogs. Neither could they find any of the usual paraphernalia that bomb-makers have around the place – wiring and batteries and kitchen timers and that kind of thing.

‘From what Sergeant Harvey was told by the British captain, the report came back that MacGreevy was fully co-operative and friendly and there was no record of him ever having been a member of a dissident group. But – and this is what the SDU failed to check up on, for some reason. If you ask me, they were probably too busy chatting with MacGreevy about the latest runners at Mallow or how to grow prize turnips, or else they decided that if there were no explosives on the premises, it wasn’t worth looking into.’

‘Go on. Don’t keep us in suspense.’

‘In each bomb the mobile phone was taped to the detonator with that sticky brown parcel tape, you know the kind of stuff. And in each bomb – including ours – there were dog hairs stuck to the tape. Only a few. In the bomb they defused at Thiepval Barracks, only two. But they were all the same greyishy colour and it’s likely they all came from the same dog, almost certainly mixed breed, but mostly Kerry Blue. We’re carrying out a DNA test on the hairs right now, and that will give us its ancestry, back to three generations anyway, as well as its approximate size and weight and appearance.’

‘Do we know if this James MacGreevy owns such a dog?’