The stairs led to a smaller hall with coombed ceilings. She stood for a moment, orientating herself, then she turned to her right. ‘This way, I think.’ She crossed the hall towards three identical doors and moved to open the furthest left. Light flooded out from the room, which was in full sun thanks to a dormer window with no curtains. The room was unfurnished, the floorboards bare, and Clare thought it felt unused. She went to the window and looked out. It afforded a clear view of the treetop walk and she guessed this was the room used by the gunman. She pushed the sash fastener back to unlock it and raised the window up. It grated a little and she saw where the paint had flaked off. She looked out and down the slates to the guttering below. No sign of anything there.

‘Reckon this is where the shot came from?’ Chris asked.

She squinted into the sun, her gaze fixed on the treetop walk, imagining Russell Fox’s last moments. He’d have been a sitting duck, up there. Nowhere to run to, even if he’d noticed the gunman. ‘Yeah,’ she said, stepping back from the window. ‘See for yourself.’ She waited while Chris checked the view. Then he, too, stepped back.

‘Has to be one of them,’ he said.

‘What, Gaby and that lot?’

‘There’s no other explanation.’

‘It’s a bit obvious,’ Clare said. ‘Even if one of them did want to do away with Russell, for whatever reason, to do it from the upstairs window of the house they were staying in… it’s a huge risk.’

‘You want to search the house for a weapon?’

She shook her head. ‘If it was one of them, they’d have got rid of the gun long before raising the alarm.’

Chris nodded. ‘All the same, the shot did come from the house. And another thing – it would have made a fair bit of noise, even with a suppressor.’

‘I know. But you saw those bins full of empties, Chris. They were probably sleeping it off on Saturday morning. Especially if he was killed early on.’

‘Suppose.’

They closed the window and left the room.

‘What now?’ Chris asked as they walked back down the stairs.

‘I’d like to speak to my contact at the prison,’ Clare said. ‘Find out what I can about Russell Fox’s time there.’

‘Clare Mackay, how are you?’ Colin Morris said, when the telephonist at Barlinnie prison finally tracked him down. ‘Sorry to keep you waiting; I was dealing with something.’

‘I’m well, thanks, Colin. You?’

‘Oh you know, same old, same old. Too many bodies, not enough cells, not enough time or money to do everything I’d like.’

‘Sounds pretty much like police work,’ Clare said.

‘So, what can I do for you?’

‘Information, if possible. Going back a few years now. Russell Fox.’

‘Name rings a bell,’ Colin said. ‘Refresh my memory.’