Free And So To Murder by John Dickson Carr

trance, ‘just inside the entrance to the sound-stage. Did you notice it?’
    ‘No.’
    ‘A page-boy sits by the door and keeps guard. He’s theoretically supposed to let people in and out. But he also runs errands and takes messages, though he isn’t allowed out of the stage. When he happens to be gone for a minute or two, and you want something done, you just take a piece of chalk and write your instructions on the blackboard.
    ‘Don’t you see it? When the page wasn’t there, somebody walked calmly up and wrote: ‘ Please tell Miss Stanton to – ’ and the rest of it; signed: T. Hackett . He could have turned out the little lamp over the blackboard, and not a soul would have seen him. I’ll bet you a fiver that’s what happened.
    ‘Then the person was all prepared. He came here and lit the gas snugly and cosily. He went upstairs with his bottle of vitriol. He knew you would come to this room. He knew you would answer the speaking-tube. And the worst of it is that the swine got the whole idea from me.’
    Monica moved back until she was touching the wall.
    This wasn’t happening. It couldn’t be.
    Her mind held a vivid picture of what would have happened if Cartwright had not flung that lump of putty and made her jump back. But revulsion was kept back by bewilderment. She felt as though the room were beginning to stifle her; as, in a literal sense, it was.
    ‘But who – ?’
    ‘I don’t know,’ said Cartwright, rubbing the side of his beard. ‘I don’t know.’
    ‘And why? I mean, why me ?’ (This was the staggering injustice.) ‘Why should anybody do that to me? I h-haven’t done anything to anybody. I don’t even know anybody here!’
    ‘Steady, now.’
    ‘It was a mistake, don’t you see? It must have been. That message must have been meant for somebody else. And yet I don’t see how it could have been. The boy said “Miss Stanton.” He said it distinctly.’
    ‘Careful,’ Cartwright said sharply. ‘There’s somebody coming.’
    He made a quick gesture. A noise of quick, firm footsteps approached outside the shattered window. In the dim gaslight, wavering with any movement, a part of a head appeared above the window-sill. It consisted of hair, forehead, eyes, and the upper part of a nose. The eyes, light blue and glistening where the dim light caught their whites, looked steadily at them.
    ‘I thought I heard a loud noise,’ the newcomer observed. ‘Is anything wrong?’
    Cartwright grunted.
    ‘You did hear a loud noise,’ he said. ‘You heard it like blazes. Excuse me. This is … by the way, what do I call you? Mr Gagern? Herr Gagern? Or Baron von Gagern?’
    2
    The appearance of that half-face, cut off by the window-ledge just below the eyes, had made Monica press back: not because the newcomer was alarming, but because he was unfamiliar. The newcomer’s fresh complexion gave him a look of youthfulness. But the straw-coloured hair, parted at one side and brushed flat round his head, had begun to turn dry and grey at the temples. There were long, fine, horizontal wrinkles in his forehead. His English was not only good; it was flawless, though slow-spoken.
    ‘Please call me what you like,’ he replied seriously. ‘I should prefer Mr Gagern, I think.’
    ‘Mr Gagern, this is Miss Stanton.’
    The eyes at the window shifted sideways. There was a noise of invisible heels being clicked together.
    ‘Miss Stanton has just found the acid,’ added Cartwright.
    ‘I do not understand what you mean.’
    ‘Come in here and you will. Somebody worked the same dodge that was used in The Doctor’s Pleasure . Somebody brought Miss Stanton here with a fake message, poured acid down that speaking-tube, and got away. Except for a lucky accident, she wouldn’t be talking to us now.’
    Gagern changed colour like a schoolboy. Then he turned his back to the window and shouted: ‘Here! This way!’
    It was surprising how quiet, in the past minutes, the whole sound-stage had become. You