‘Okay, I have you,’ said Peadar, and glared at his fingertip as if it had mortally offended him.

‘Now lift up your hand and press your fingertip down on the top of your head. But keep staring at it. Imagine that you can look upwards right through your brain and your skull and you can see that fingertip just as clearly as you did before. Keep staring up at it.’

Again, Peadar did as he was told, and pointed his fingertip into his wispy white hair. At the same time, he rolled up his eyes so that he was keeping his gaze fixed on where it was, even if he couldn’t actually see it. Within only a few seconds, his eyelids closed.

‘Keep looking at that fingertip, Peadar,’ said Dr Power. ‘Keep looking at it and think back to that moment when you first saw Roisin pushing her baby along The Marina.’

Peadar was silent for almost half a minute, but the two detectives could see that his chest was rising and falling more slowly as he breathed, and he started to make a high-pitched wheezing sound, as if he were asleep. His right hand suddenly dropped down to the arm of his chair and his cigarette fell on to the shaggy chocolate-coloured hearthrug. Detective Cullen picked it up and tossed it into the fire.

‘Can you see Roisin coming?’ asked Dr Power.

‘Roisin…’ said Peadar, in a blurry voice. He sounded like somebody talking in another room. ‘How’re ye going on, girl? I don’t never normally see you at this time of day.’

‘What happens now, Peadar?’

‘What? Oh, I’m telling Roisin all about Sinéad… my little Sinéad. Then she says that Ita’s poorly and she has to take her home, and into the warm.’

‘When do you first see the feller in the grey tracksuit?’

‘I can hear him… I can hear him now. Like, his rubber dollies are slapping along the path, slap-slappity-slap. And it sounds like he’s running, so I turn around. He’s left the path now and he’s crossing the grass towards Roisin, and he’s going faster and faster and his arms going like them connecting rods on a steam engine.’

‘Can you see his face at all?’

‘No… he has his hood up… and by the time I turn around he’s like side-on to me.’

‘Is there any hair protruding from his hood?’

‘No. It’s pulled too far down. I can see the end of his nose but that’s all.’

‘Is he wearing gloves?’

Even though his eyes were closed, Peadar leaned forward as if he were trying to focus more narrowly on something that he could see in front of him.

‘Yes,’ he said at last. ‘He’s wearing gloves all right. Grey knitted gloves by the look of them.’

‘And how about his trainers? What does he have on his feet?’