He looked around the sorry little room. There was a makeshift bed upon the floor, only a pile of straw and some filthy sheets. There was a gin bottle and two glasses next to it on the bare boards, alongside a plate and a knife. Barely a crumb remained of whatever she had been eating. The rats had seen to that too.

The room’s only other piece of furniture was the table Mary had been sitting at when she fell. It had on it a pen, a bottle of ink and a pile of papers. Raven picked the first sheet up and read the heading:

MY TESTIMONY AND CONFESSION

MARY MACDONALD

He rifled through the leaves, too impatient to focus in depth, individual phrases and details catching his eye. A brutal childhood in Glasgow, abandoned to an orphanage, adoption by Mrs Dempster, further cruelties inflicted upon her there. But it was not merely a catalogue of how she was sinned against. It was a stated admission of her crimes. A confession indeed.

Raven turned hurriedly to the final page.

I am about to take my own life because I am afraid of what I have become, and afraid of who I will hurt next. When Martha told me people had been asking questions about the deaths of my patients, I was forced to confront how I would feel were she to discover what I am and all that I have done. I write this not in the hope that Martha will forgive me, or even understand, but because I have come to accept that she deserves to know the truth.

He flipped back through the sheaf and started reading more closely. The stench in his nose was telling him he should take the pages and resume reading somewhere else, but he was impatient to find out all he could. However, he had barely begun before he became aware of the echo of voices from in the stairwell, the hurried thump of feet upon wood. He looked up to see McLevy’s man bound through the door. His colleague almost ran into the back of him as he stopped to take in the gruesome sight he had encountered.

‘Dr Raven, I am John Soutar, police officer and assistant to Mr James McLevy.’

‘I know who you are. It is as well you are here, as you can see, though you don’t know the half of it.’

‘Bind him, Tommy,’ Soutar commanded the other man. ‘And take care to bind him well. He is wanted for murder.’

Raven reeled, looking from Soutar to the corpse. He wondered for a moment whether Martha Dempster had somehow laid a trap for him but didn’t see how that could be or how it might profit her.

‘What are you talking about? This one’s been dead for days. I just got here. She took her own life. She has even left a testimony explaining why.’