He pointed at the double swing doors that led into the backstage corridor.

‘Did you find out what it was?’ Hawthorne asked.

‘Yeah. It was really strange. It turned out that one of the light bulbs had exploded. I can’t imagine how that happened because there was nobody around. I had to get a dustpan and brush and look here … !’ He held out his hand, showing us a cut on his finger. ‘I did that picking up the pieces. I was looking for a plaster when Tirian came up and told me about the review and the party finishing. Maybe the light bulb was a bad omen!’

‘Does that happen often? Electrical appliances blowing up?’

‘Well, I haven’t been here very long so I can’t say. But a lot of the fittings in this theatre are very old. Maybe it’s haunted? I don’t know.’

Keith handed over the key to the green room – an old, prison-style key on a wooden block – and we passed through the swing doors. It seemed strange to me that he’d recognised Harriet Throsby. He’d seen a photograph of her in another theatre – and one that had been defaced. It surely wouldn’t have been easy to pick her out in a crowd, the image projected onto a blurry black-and-white TV.

I said as much to Hawthorne.

‘She had quite distinctive looks,’ he said. ‘You recognised her too.’

‘I’d seen her at the Old Vic,’ I countered, back on the defensive.

We reached the staircase. Looking around me, I noticed that both upstairs and downstairs, the backstage area was brightly lit. ‘Do you think someone broke the bulb deliberately?’ I asked.

‘It’s possible.’

‘Maybe they were trying to hide something,’ I suggested. ‘There was something they didn’t want Keith to see too clearly.’

‘That’s possible too.’

Hawthorne had nothing more to add. We continued downstairs, past the dressing rooms and back underneath the stage-door manager’s office. The green room was in front of us. Hawthorne unlocked the door and we went in.

I wasn’t sure what he expected to find, but the room was exactly as I remembered it: warm and secluded, a refuge from difficult audiences and bad reviews. It had been dark and raining when we had gathered here on the first night. Now it was early evening and the weather had improved – not that either of these things made much difference. The glass in the window was frosted and even if we’d been able to look out, the alleyway wouldn’t have allowed much light to penetrate. I thought I could smell alcohol, but that was probably the carpet. Instinctively, I ran my eyes over the various surfaces, hoping to see the dagger I had been given and which, after all, I might have forgotten and left behind. Of course it wasn’t there. The last time I’d seen it, it had been in Cara Grunshaw’s evidence bag.

It should have been obvious all along, but I’m afraid the truth of my situation only occurred to me at that moment. Somebody had taken my dagger. They had done it quite purposefully, using a towel or a plastic bag to make sure that they didn’t add their fingerprints to my own. In other words, long before Harriet Throsby was killed, they had decided to frame me. Somebody hated me. And it could only be one of seven people.