‘And you think he was pushed?’ Rebus tried not to sound cynical.

Her reply was blunt. ‘Yes, I do.’

‘By this angel who’s managed to put up with him all these years?’

‘That’s right.’

‘OK, Doc, so point me to the medical evidence.’

‘Well, it’s a narrow staircase, pretty steep, about eleven or twelve steps, say. If you weighed around thirteen stone, and happened to slip at the top, you’d sort of be bounced off the sides as you fell, wouldn’t you?’

‘Perhaps.’

‘And you’d try to grab hold of something to stop your fall. There’s a banister on one wall. They were waiting for the council to come and fit an extra banister on the other wall.’

‘So you’d reach out to grab something, fair enough.’ Rebus drained the sour black coffee and studied the pile of work in his in-tray.

‘Well, you’d have bruising, wouldn’t you?’ said Patience Aitken. ‘Grazes on your elbows or knees, there’d be marks where you’d clawed at the walls.’

Rebus knew that she was surmising, but could not disagree thus far. ‘Go on,’ he said.

‘George Gallagher only has significant marks on his head, where he hit the floor at the bottom of the stairs, breaking his neck in the process. No real bruising or grazing to the body, no marks on the wall as far as I can see.’

‘So you’re saying he flew from the top landing with a fair bit of momentum, and the first thing he touched was the ground?’

‘That’s how it looks. Unless I’m imagining it.’

‘So he either jumped, or he was pushed?’

‘Yes.’ She paused again. ‘I know it sounds tenuous, John. And Christ knows I don’t want to accuse Grace of anything…’

Rebus picked up a ballpoint pen from beside the telephone and scrabbled on the surface of his desk until he found the back of an envelope upon which to write.

‘You’re only doing your job, Patience,’ he said. ‘Give me the address and I’ll go pay my respects.’