‘Haven’t you been listening? How many times do I have to tell you? It had nothing to do with Mindgame.’

‘Then … why?’

Tirian was slumped in his chair, silent, crying. He hadn’t even tried to deny what Hawthorne was saying. The other actors, Martin Longhurst, Ahmet and especially Maureen were staring at him in horror.

‘Let’s start with the night of the party,’ Hawthorne suggested, calmly. ‘Tirian had decided to kill Harriet before he even left the theatre. We’ll come to the reason in a minute. When Jordan Williams made his death threat, it provided Tirian with an opportunity he couldn’t ignore. Jordan would be the scapegoat. Easy enough to nip upstairs and nick one of his hairs off a brush or a towel – but he also needed the dagger with Jordan’s fingerprints. That would be the clincher.

‘He was the first to leave the green room – at about twenty minutes past midnight. He signed out at twelve twenty-five. But he knew he’d have to come back when the theatre was locked for the night and there was only one way in: the fire exit, which only opened from the inside. So what he did was, he nicked a packet of Ahmet’s cigarettes, which he was going to use as a wedge. He’d push the bar to open the door into the alleyway and then slide the packet underneath to make sure it never completely shut.

‘But he had a problem. He knew that Keith was sitting in front of the TV screens in the stage-door office and the lights in the basement corridor were too bright. When he opened the door, light would spill outside and there was a good chance that Keith would see it – even on a black-and-white TV, a shaft of light is one thing you can’t miss – and maybe he’d come to investigate. So he nipped upstairs, probably stole the hair from Jordan’s dressing room at that time, and then smashed a light bulb.’ Hawthorne glanced at me. ‘He didn’t do it to darken the corridor. He was just creating a diversion. Immediately afterwards, he ran back down and opened the fire door while Keith was dealing with the broken glass. Now everything was set up. He waited a moment or two, went back upstairs and left through the stage door – making sure he chatted with Keith so that everything would look normal.

‘He didn’t take the train to Blackheath. At least, not then. He came back to the theatre in the middle of the night, by which time he assumed everyone had left – although he didn’t realise that Jordan was sound asleep in his dressing room. That didn’t matter. He snuck back in through the fire exit, chucked the crumpled packet into the bin and stole the first dagger he saw, which happened to be the wrong one. Incidentally, one person noticed that the fire exit was open when they left the green room. That was Ewan Lloyd. He told me that he had a chill at the back of his neck – he thought it was some sort of premonition. He didn’t realise … It was a cold night and all he’d felt was the draft from the slightly open door.