Ailsa took a side corridor and opened another door that led out into the warm night. Ahead was a solitary tree and some iron railings. She took a moment to breathe in the night, listening to the occasional social roar from the city’s closest public houses and the intermittent traffic along Cowgate before looking to Connie for an answer.

‘Personal experience,’ Connie said. ‘Did we swap professions without me realising?’

‘Touché, but you don’t just look at a crime scene and assess whether or not an offender is high or low IQ, you try to get inside their head. What I just witnessed steps beyond the border of being clinical. When you touch a corpse, interact with it, you create a bond. Flesh does not need to be living for us to feel a sense of responsibility towards it, or a desire to act kindly. Do you not find it puts something of a dent in your objectivity to get so intimate?’

‘Everything I do is about figuring out motive. In this case, the motive will tell us whether or not he plans to kill again. My role is nothing like as intimate as yours. You take bodies apart, look within the most secret places. You move your hands around inside guts, literally touch brains. Nothing is hidden. I find it reassuring that if I die in unforeseen circumstances, someone like you will be here, following every pathway, inspecting every cell until you know what happened. A reckoning is important, even if it’s after you’re dead,’ Connie said.

‘Reckoning is an emotive term,’ Ailsa noted. ‘What conclusions have you drawn in this case so far?’

‘I don’t think he planned to kill the first time, so it doesn’t seem as if that’s his agenda. I’m more concerned that he’s so ill-prepared for his victim’s reaction that killing is something he’ll do again by accident. Perhaps that’s why he was more careful when he took Elspeth Dunwoody. I believe she’s still alive, I’m just not sure why. There was a psychosexual force at play with Angela. She intrigued him. He didn’t want just any woman – he wanted her. Not to dominate and hurt her but, God, I guess, to cuddle her. I don’t know why I’m more grossed out by that than the thought of cold, hard violence.’

‘Violence is primeval. This is the sort of blurred-line killing that makes us all feel stalked. He’s a monster wearing mittens,’ Ailsa said.

‘You just coined the phrase “a monster wearing mittens”? And you were worried about me lying next to a corpse.’

Baarda walked out into the darkness behind them.

‘Sorry to interrupt. Bad news, I’m afraid. A twelve-year-old girl has gone missing, believed abducted. MIT are calling their officers back to that as a priority. Did you get the answers you were looking for?’