‘It’s a still from a night-vision camera, but would you say this was your Mr Edwards?’

The head took it and then handed it to Miss Lloyd. ‘I’d say it is. What do you think, Emily?’

‘Oh yes, Mr Lewis, that’s Mr Edwards, I’m sure of it. He’s so thin, isn’t he?’ She handed it back to Jackman. ‘He’s such a caring man too. Always got time for the children’s questions. I’m sure he’s inspired a lot of them to do their bit for the planet and our endangered species.’

Marie gritted her teeth. So, for the past month, a murderer had been teaching conservation to a school of impressionable children. Great. Just great.

‘We need to speak to him immediately, Mr Lewis. Can you page him over your loudspeaker system?’ Jackman said.

Looking somewhat confused, Lewis turned to his secretary. ‘Could you ask Mr Edwards to come immediately to the general office, please?’

A few moments later, the request was heard echoing around the school corridors. Marie already knew there would be no response.

‘This biology lab, where is it?’ Jackman was on his way through the door.

‘I’ll take you.’ Jonathan Lewis caught him up. ‘It’s this way, but we did search it and there was nothing there at all.’

Marie hurried along beside them. ‘We are rather more interested in where this part of the building is situated. If that’s the last time Davy was seen, then there’s a good chance that’s where he disappeared from.’

The lab was situated in a spur off a main corridor. It was a large room flanked by plate glass along one wall and boards that resembled their own whiteboards along the other. The equipment was all up-to-the-minute. Posters and diagrams and notices occupied the facing wall, and in the far corner, a fire door.

‘CCTV on that?’ snapped Jackman.

‘Er, I think so, although it is probably an external camera,’ said Lewis.

Marie looked outside. There was a camera high up on top of a pole close to the perimeter fence. A narrow walkway led through to what appeared to be another car park. ‘What’s that?’ she asked, pointing to the end of the walkway.

‘Staff parking, I’m afraid,’ said Lewis, in a grave voice. He was beginning to realise what had happened.

‘Okay, back to the office. We need to get Simon looking at this area in particular, including the car park. And you, Mr Lewis, are going to tell us everything you know about Edwards, and how the hell he came to be here in the first place.’