The expressions on the faces of the other officers present — a grim mixture of nauseated, depressed, tense and stoical — told the same story. Whatever they’d just witnessed had affected every one of them, and the eyes of DC Rodriguez were wet with tears.

‘What have we got then?’ asked DCI MacLeod, his soft Edinburgh burr somehow easing the tension in the air. There was a quiet decency about MacLeod that naturally drew people to him, as did his air of calm unflappability, that made you look beyond the beer belly, the thinning grey hair and unfashionable moustache, and see only a natural leader. Once again, Tina was glad she worked for him.

‘We’ve found stuff on here,’ sighed Grier, running a hand roughly across his face as if he were trying to remove the memory of whatever it was. ‘Films.’

‘What kind?’ asked Tina, feeling a twitch of morbid excitement.

‘Footage of the murder of two of the victims. It looks like he filmed it himself.’ Grier paused. ‘It’s extremely graphic.’

‘It’s more than that,’ said DS Simon Tilley, normally an exuberant copper with a big personality and a laugh like a bass drum, but who was also the father of two young children. ‘It’s the worst thing I’ve ever seen.’

MacLeod took a deep breath. A father himself, he clearly had little appetite for the task ahead, but was far too professional to let that stop him. ‘We’d better take a look then.’

He turned to Tina, his expression suggesting she didn’t have to watch if she didn’t want to. She noticed some of the others looking at her, including Grier and Rodriguez, and had this feeling they were willing her to back out of it.

‘Don’t worry,’ she told MacLeod bluntly without looking at them. ‘I can take it.’