Kyna didn’t dislike men, but she liked them scruffy and funny and openly affectionate, and they had to be Ariana Grande fans.

‘I’m going to see Brendan after,’ said Katie. ‘There’s no way that we can leave this hanging in the air between us, unspoken.’

‘Well, good luck with that.’

There was a knock at the door. Moirin cautiously opened it, and said, ‘Dr Power is here, ma’am, along with DI Mulliken and DS Begley.’

‘That’s grand, Moirin. Please show them in.’

Dr Power came walking briskly up to Katie with her hand held out. She was in her mid-fifties, with a blonde Dutch bob and a scarlet trouser suit. She had huge emerald-green eyes that were lit up as if she were already excited about their meeting.

Detective Inspector Mulliken and Detective Sergeant Begley followed her in, and by the sly, amused glances they were sharing, Katie could tell that Dr Power had already been rattling on to them as they escorted her up here. Katie had met her before, at several criminology seminars in Dublin, and she knew how garrulous she could be. She had heard one professor call her ‘the Mouth of the Liffey’.

‘How are you, Kathleen?’ she said. ‘Do you know it’s been almost a year since I was here in Cork? A year! I can’t think where the time goes flying off to!’

Katie introduced her to Kyna and then they all sat down on the couches by the window. Katie couldn’t help noticing that six or seven hooded crows had gathered on the rooftop opposite, and that more were flapping in to join them. She hoped it wasn’t an omen. Whenever the crows gathered, something always seemed to go badly or even tragically wrong. They had gathered on the morning that Conor had died.

‘I don’t know if you saw, but Dr Power recently had a new book out about criminal psychology,’ Katie told Kyna.

‘Murder Most Explicable,’ said Dr Power. ‘It’s twenty-second this week in the Irish Times bestseller list. And please call me Ailbe.’

‘You’ve read all the background I sent you on the Lee Pusher?’ Katie asked her.

Dr Power reached into her red bucket bag and took out a folded sheaf of papers. ‘I read them on the way down here. His victims are all very varied, aren’t they – in age, in sex, in background – so I think we can safely say that he picks them totally at random. All they seem to have in common is that they were walking along the riverbank at a location where there’s no wall nor railings.’

She unfolded a map of the Lee between the Daly footbridge at Sunday’s Well to the west, and Blackrock Castle to the east, where the river widened into Lough Mahon. She had marked with black crosses all the seven sites where the Lee Pusher had knocked his victims into the water.