Anthony Horowitz - The House of Silk

‘Your words, I think, fall on deaf ears, Mrs Carstairs,’ Holmes remarked.

And it was true. From the moment that Holmes had made his extraordinary declaration, Carstairs had been gazing in front of him with an expression of peculiar horror that suggested to me that some small part of him must have always known the truth, or at least suspected it, but now, at last, he was being forced to stare it straight in the face.

‘Please, Edmund…’ She reached out to him, but Carstairs flinched and turned away.

‘May I continue?’ Holmes asked.

Catherine Carstairs was about to speak but then relaxed. Her shoulders slumped and it was as if a silken veil had been torn from her face. Suddenly she was glaring at us with a hardness and an expression of hatred that would have been unbecoming in any English gentlewoman but which had surely sustained her throughout her life. ‘Oh yes, oh yes,’ she snarled. ‘We might as well hear the rest of it.’

‘Thank you.’ Holmes nodded in her direction, when went on. ‘After the death of her brother, and the destruction of the Flat Cap Gang, Catherine O’Donoghue — for that was her given name — found herself in a situation that must have seemed quite desperate. She was alone, in America, wanted by the police. She had also lost the brother who had been closer to her than anyone on this planet, and whom she must have dearly loved. Her first thoughts were of revenge. Cornelius Stillman had been foolish enough to boast of his exploits in the Boston press. Still in disguise, she tracked him down to the garden of his house in Providence and shot him dead. But he was not the only person mentioned in the advertisement. Reverting now to her female persona, Catherine followed his junior partner onto the Cunard liner, the Catalonia. It is clear what was on her mind. She no longer had any future in America. It was time to return to her family in Dublin. Nobody would suspect her, travelling as a single woman, accompanied by a maid. She took with her what profits she had been able to save from her past crimes. And somewhere in the middle of the Atlantic she would come face to face with Edmund Carstairs. It is easy enough to commit murder on the high seas. Carstairs would disappear and her revenge would be complete.’

Holmes now addressed Mrs Carstairs directly. ‘But something changed your mind. What was it, I wonder?’

The woman shrugged. ‘I saw Edmund for what he was.’

‘It is precisely as I thought. Here was a man with no experience of the opposite sex apart from a mother and a sister who had always dominated him. He was ill. He was afraid. How amusing it must have been for you to come to his aid, to befriend him and finally to draw him into your net. Somehow you persuaded him to marry you in defiance of his own family — and how much sweeter this revenge than the one you had originally planned. You were intimately connected to a man you loathed. But you would play the part of the devoted wife, the charade made easier by the fact that you have chosen to sleep in separate rooms and, I fancy, you have never allowed yourself to be seen in a state of undress. There was the inconvenience of that tattoo, was there not. So were you ever to visit a pleasure beach, you would naturally be unable to swim.

‘All would have been well but for the arrival of Bill McParland from Boston. How had he picked up your trail and learned your new identity? We will never know, but he was a detective, a very good one, and doubtless had his methods. It was not your husband he was signalling outside this house and at the Savoy. It was you. By this stage, he was no longer interested in arresting you. He had come here for the money he was owed and his desire for it, his sense of injustice, his recent wound — all this drove him to desperation. He met with you, did he not?’

‘Yes.’

‘And he demanded money from you. If you paid him enough, he would let you keep your secret. When he handed your husband that note, he was effectively warning you. At any time, he could reveal everything he knew.’

‘You have it all, Mr Holmes.’

‘Not all, not quite yet. You needed to give McParland something to keep him quiet but had no resources of your own. It was therefore necessary to create the illusion of a burglary. You came down in the night and guided him to the correct window with a light. You opened that window from inside and allowed him to climb in. You opened the safe, using a key which you had never in fact lost. And even here you could not resist a touch of malice. As well as the money, you gave him a necklace which had belonged to the late Mrs Carstairs and which you knew had great sentimental value to your husband. It seems to me that any chance you had to hurt him was irresistible to you and you always seized it with alacrity.

‘McParland made one mistake. The money that you gave to him — fifty pounds — was only a first payment. He had demanded more and, foolishly, he gave you the name of the hotel where he was staying. It is possible that the sight of you in all the finery of a wealthy English lady deceived him and he forgot the creature you had once been. Your husband was at the gallery in Albemarle Street. You chose your moment, slipped out of the house and climbed into the hotel through a back window. You were waiting in McParland’s room when he returned and struck from behind, stabbing him in the neck. I wonder, incidentally, how you were dressed?’

‘I was dressed in my old style. Petticoats and crinolette would have been a little cumbersome.’

‘You silenced McParland and removed any trace of his identity, missing only the cigarette case. And with him gone, there was nothing to stand in the way of the rest of your scheme.’

‘There is more?’ Carstairs rasped. All the blood had left his face and I thought he might be about to faint.

‘Indeed so, Mr Carstairs.’ Holmes turned back to the wife. ‘The cold-blooded marriage that you had arranged for yourself was only the means to an end. It was your intention to kill Edmund’s family one at a time: his mother, his sister and then he. At the end of it, you would inherit everything that had been his. This house, the money, the art… all of it would be yours. It is hard to imagine the hatred that must have been driving you forward, the relish with which you went about your task.’

‘It has been a pleasure, Mr Holmes. I have enjoyed every minute of it.’

‘My mother?’ Carstairs gasped the two words.

‘The most likely explanation was the one you first suggested to me, that the gas fire in her bedroom blew out. But it was not one that stood up to scrutiny. For your manservant, Kirby, told us that he blamed himself for the death as he had stopped up every crack and crevice in the room. Your mother disliked draughts so it was impossible that a draught could have blown out the fire. Your sister, however, had come to another conclusion. She believed that the late Mrs Carstairs had taken her own life, so distraught was she at your marriage. But as much as Eliza loathed your new wife and instinctively knew her to be dissembling, even she was unable to arrive at the truth, which is that Catherine Carstairs entered the room and deliberately blew out the flame, leaving the old lady to perish. There could be no survivors, you see. For the property to be hers, everyone had to die.’

‘And Eliza?’

‘Your sister is being slowly poisoned.’

‘But that’s impossible, Mr Holmes. I told you—’

‘You told me that you have carefully examined everything she has eaten, which only suggests to me that she is being poisoned in another way. The answer, Mr Carstairs, is the bath. Your sister insists on bathing regularly and uses strong, lavender bath salts. I must confess that this is a most novel way of administering poison, and I am frankly surprised that it has been so effective, but I would say that a small measure of aconitine has been added, regularly, to the bath salts. It has entered Miss Carstairs’s system through her skin and also, I would imagine, through the moisture and the fumes which she has, of necessity, absorbed. Aconitine is a highly toxic alkaloid which is soluable in water and which would have killed your sister instantly if a large dose had been used. Instead, you have noted this slow but remorseless decline. It is a striking and innovative method of murder, Mrs Carstairs, and one which I am sure will be added to the annals of crime. It was also quite daring of you, incidentally, to visit my colleague while I was incarcerated, although you naturally pretended you knew nothing of that. It doubtless persuaded your husband of your devotion to your sister-in-law while, in fact, you were actually laughing at them both.’