He took them through the large kitchen, past a big sagging sofa covered in felt-tip pen marks and a large tea stain. An overflowing box of toys sat between the edge of the sofa and the glass back wall looking out over the garden. The glass had been retracted, allowing the three of them to step out onto wooden decking. Erika savoured the drop in temperature. Floodlights had been put up in the back garden, which Erika could see extended down to a murky thicket of trees, where several figures in overalls were crouched down, examining the grass.

They doubled back down a narrow gravel passage along the outside glass wall and came to a sash window, which was level with the sink in the kitchen. A drain below was giving off an evil, vomit-like smell.

‘We’ve dusted the window, the gutter pipes, the window of the house next door,’ Nils said. ‘Nothing. We did find this, though.’ He turned their attention to the base of the white-painted sash window. ‘See here, in the wood?’ His latex-gloved finger hovered over a small square impression in the gloss paint, no more than half a centimetre wide. ‘The window was forced up using a blunt flat instrument, perhaps a screwdriver.’

‘This window was closed when you arrived on the scene?’ asked Erika.

‘Yes.’

‘Good work,’ she said, looking back at the tiny impression in the paint. ‘Were there any footprints you could get from the gravel here?’

‘A mixture of vague impressions, could be a small pair of feet, but nothing we can make a cast from. Now, if we can come back inside,’ said Nils. They followed him back round the house, through the glass doors, into the kitchen to the other side of the sash window.

‘Can you see here, there should be sash stops,’ said Nils, indicating two small square holes on either side of the sash window frame.

‘What’s a sash stop?’ asked Moss.

‘Two small plastic hooks, which work on springs poking out of the inside of the upper second sash frame. They are there to stop the bottom frame of the window from being forced upwards. They’ve been removed.’

‘Could Gregory Munro have removed them?’ asked Erika.

‘Not if he was worried about being burgled, which I think he was. The house has a top-of-the-range security system. Motion sensor lights in the back garden. When the power was cut, it should have triggered the alarm. That’s what they are designed to do – but nothing.’

‘So, whoever did this removed the sash stops from this window and knew the combination of the security alarm?’ asked Erika.

‘Yes, it’s a theory,’ said Nils. ‘There’s one more thing.’ He took them back out through the glass doors. When they reached the bottom of the garden, they ducked down to look under the tree and found the wire fence had been propped open.

‘The garden backs on to the train tracks and the Honor Oak nature reserve,’ said Nils. ‘I think this was the access point. Fence was clipped with wire cutters.’

‘Shit,’ said Moss. ‘Who the hell do you think did this?’

‘We need to find out more about this Dr Gregory Munro,’ said Erika, staring up at the house. ‘That’s where we’ll find our answers.’

5

It was an old desktop PC on a large creaky metal stand with wheels, tucked in under the stairs of a modest house. The chat room home screen popped up. It was basic, no fancy graphics. The mainstream chat rooms were moderated, but this one occupied the backwaters of the Internet where the pond scum could thrive.

There was a beep on the screen and the name of a user called DUKE flashed up and started to type.

DUKE: Any1 up?

The hands moved fast across the keyboard, eager to talk.

NIGHT OWL: I’m always up, Duke.

DUKE: Night Owl, where you been?

NIGHT OWL: Busy. I’ve gone three days straight without sleep. Almost my record.

DUKE: My record is four. The crazy, trippy hallucinations were almost worth it. Naked girls. So real ***bites knuckle***

NIGHT OWL: Ha! I wish my hallucinations were so friendly. I can’t stand to have the lights on, they cause me pain… But then the shadows seem to come alive. Blank eyeless faces watch me from the corner of my eyes. And I see him.

DUKE: You having a tough time of it?

NIGHT OWL: I’m used to it… You know.

DUKE: Yeah. I do.

DUKE: So? Did you do it?

NIGHT OWL: Yes.

DUKE: Seriously?

NIGHT OWL: Yes.

DUKE: You used the suicide bag?

NIGHT OWL: Yes.

DUKE: How long did it take?

NIGHT OWL: Almost four minutes. He fought against it, despite the drugs.