Dick stared at him.
'A waste of effort? Why?'
'Because the marksman with the rifle, and the poisoner who killed De Villa with prussic acid, are one and the same person.'
Again the summons of the front door-bell shrilled out strongly, from the buzzer over their heads. Dick's own head was spinning. Dr Fell's words seemed quite literally to make no sense. He had a mad vision -derived from the cheaper thrillers, where anything is possible - of the murderer firing at Sam De Villa some fantastic bullet containing a hypodermic injection of prussic acid to pierce the victim's arm.
Again the door-bell shrilled. Lesley hastened to answer it; and, though Dick had meant to seize her arm and restrain her, she got away from him. From the corner of his eye he saw, as Lesley opened the front door, that the visitor was only Superintendent Hadley, and he could relax his vigilance. For he was blindly obsessed now, concentrated on Dr Fell, trying to grope closer to an explanation which he sensed as there yet always eluding him.
'Let's get this quite straight!' Dick pleaded. 'You say that the murderer ...'
Dr Fell spoke with toiling patience.
'The murderer,' he said, 'killed Sam de Villa by injecting a hypodermic of prussic acid into his arm.'
'In the sitting-room?'
'Yes. In the sitting-room.'
'And then?'
'Then the murderer slipped out of the sitting-room ...' 'Leaving the room all locked up behind him?' 'Yes. Leaving the room all locked up.' 'But how?'
'We're coming to that,' said Dr Fell imperturbably. 'I ask you merely to follow this elusive person's movements. The murderer injected the prussic acid, which would render De Villa unconscious almost at once but would take two minutes or more to render life extinct. The murderer then left the room -'
(Windows locked. Door locked and bolted.)
'- and put through a phone call to you, summoning you there, from the telephone outside in the hall. The murderer waited until you were on your way, and dropped a shilling into the electric meter: thus turning on the light in the sitting-room.
'Having now a good light to see by, the murderer ran across the lane, hid behind the wall, and with the stolen Winchester 61 fired in the direction of the window.'
'At a dead man?'
'At a dead or dying man, yes.'
'Even though die room was already locked up on the inside?' 'Yes.'
'But why?'
'Because the whole scheme could never have succeeded otherwise,' replied Dr Fell.
'Hoy!' interposed the bellow of an angry voice, which for some seconds had been trying to attract their attention. Dick was only now conscious of it.
Superintendent Hadley came into the dining-room. Over his shoulder they heard him say, 'Stand by,' before he closed the door after him. Hadley's countenance was grim and hard under the bowler hat, even with a suggestion of pallor which scared Dick still more. Hadley put his big hands together and cracked the knuckle-joints.
'Fell,' he said harshly, 'are you insane?'
Dr Fell, who had been keeping on Dick Markham eyes almost as hypnotic as those of the bogus Sir Harvey Gilman last night, did not reply.
' I've been expecting you,' Hadley went on,' to come over to the place where that woman was murdered. I came over here to find out what the devil was the matter with you. And it's a good thing I did.' It was not pallor in Hadley's face so much as an evil greyish tinge. 'Because I discover -'
'Not yet, Hadley,' said Dr Fell, turning his head round briefly. ' For God's sake not yet!'
'What do you mean, not yet? Miller tells me...'
Dr Fell got to his feet, with the imploring gestures of one who urges calm and serenity. He seemed trying to ignore Hadley, to shoo the superintendent away, to pretend that Hadley did not even exist And still he addressed Dick Markham.
'When I first came in here,' he said, 'I remarked - er - that it was a trifle warm. Harrumph. Yes. So it was. I drew back the curtains on these windows. But that, I am afraid, was not the main reason why I drew back the curtains from the windows, which, you notice, are open. Please observe the windows!'
Yet, as the big voice grew more rapid, Dick had an eerie conviction that Dr Fell was not in the least interested in the windows as such. He was talking at them, talking out of them, making his voice carry; any topic of conversation, it seemed, would do.
'You observe,' he insisted, 'the windows?'
'Look here!' roared Hadley.
'What about the windows?' demanded Dick Markham.
The three speeches seemed to rattle on top of each other.
'They are, as you see, ordinary sash-windows. Such as you or Hadley or I might have in our own homes. This one here is raised. But I pull it down... so.'
The window closed with a soft thud.
'When the window is unlocked, as it is now, you note that the fastening of the metal catch lies flat back: parallel with the window glass and the joining of the sashes, turned to the right. But suppose, my dear boy, I wish to lock the window?'
This was the point at which Dick noticed for the first time that Lesley Grant was not in the room.
She had not returned; she had not come with Hadley. And the Superintendent, with his hard face grim under its greyish complexion, stood like a man who intends trying a wrestling-bout with the devil. A sudden suspicion, which he thought he had fought successfully away from him, flowed back into Dick's mind ...
'Dr Fell,' he said, 'where is Lesley?'
Dr Fell pretended not to have heard. Perhaps he did not hear.
'Suppose, my dear boy, I wish to lock the window? I take hold of the thumb-grip of this metal catch. I pull it towards me and turn it towards my left. Like this! The catch swings round into its socket; it now projects straight out towards me, at right angles to the sash; and the window is locked.' 'Dr Fell, where is Lesley?'
'You observe, my dear boy, that the catch projects straight out towards me? And, therefore -'
He paused, having now no need to go on. For the last time in this case, but with a shattering distinctness which made the whole house shake, they heard the explosion of a gunshot.
Dr Fell, his big red face reflected with nightmare quality in the black shining glass of the window, did not turn round. They stood there for a second or two like three men paralysed. Then Dick slowly raised his eyes to the ceiling.
He knew where the explosion of that shot had come from. It had come from Lesley's bedroom, just overhead.
'You bloody idiot!' shouted Hadley. He stared at Dr Fell, and more than suspicion dawned in his eyes. 'You let this happen!'
Dr Fell's voice sounded muffled against the glass of the window.
' I let it happen. God help me, yes.' 'Suicide?'
' I rather think so. There was no other way out, you see.'
'No!' cried Dick Markham. 'No!'
He was not sure whether he could move, for his legs seemed turned to water and he could not even trust his eyesight. The image of Lesley, of Lesley's brown eyes; the thought of Lesley, and how much he loved her, and would continue to love her until - the iron phrase rang again - until death did them part; these things caught at him and maddened him and spun his nerves into a whirlpool that would not let go.
Then he found himself running for the door.
Hadley was running too; they crashed into each other in the doorway as Hadley got the door open, but the events took place in such a void that Dick could not even hear what the superintendent was saying.
Bright lights shone in the hall. Bert Miller, moving rapidly for so heavy a man, was already on his way up the staircase at the rear. Bert's footsteps made no noise on the staircase carpet, or perhaps Dick Markham could not hear it.