I heard the noise of the door chain at Fernly Park and then Parker stood in the open doorway.

'Where is he?' I demanded. 'Have you telephoned the police?'

'The police, Sir?' Parker stared at me.

'What's the matter with you, Parker? If your master has been murdered...'

'The master? Murdered? Impossible, Sir!'

'Didn't you telephone me, not five minutes ago, and tell me that Mr Ackroyd had been found murdered?'

'Me? Oh! No indeed, Sir.'

'I'll give you the exact words I heard. "Is that Dr Sheppard? Parker speaking. Will you please come at once, Sir? Mr Ackroyd has been murdered."'

'A wicked joke to play, Sir,' Parker said in a shocked voice.

'Where is Mr Ackroyd?' I asked.

'Still in the study, Sir. The ladies have gone to bed, and Major Blunt and Mr Raymond are in the billiard room.'

'I think I'll just look in and see him,' I said.

I passed through the door on the right of the main hall, into the small inner hall which led to Ackroyd's study. A small flight of stairs to the left went up to his bedroom. I tapped on the study door. There was no answer and the door was locked.

'Allow me, Sir,' said Parker, who had followed me. He dropped on one knee and looked through the keyhole. 'The key is in the lock, Sir,' he said, rising. 'Mr Ackroyd must have locked himself in and fallen asleep.'

I shook the handle and called out, 'Ackroyd, Ackroyd, it's Sheppard. Let me in.'

And still - silence. I picked up a heavy oak chair and hit the door with it. At the third blow the lock broke. Ackroyd was sitting as I had left him, in the armchair in front of the fire. His head had fallen sideways, and just below the collar of his jacket, was a shining piece of metal.

'Stabbed from behind,' Parker murmured. 'Horrible!' He stretched out a hand towards the handle of the dagger.

'You mustn't touch that,' I said sharply. 'Go and telephone the police. Then tell Mr Raymond and Major Blunt to come to the study.'

'Very good, Sir.'

***

When our local inspector, a man called Davis, and Police Constable Jones arrived, Ackroyd's secretary, Geoffrey Raymond, and Blunt, were in the study with me.

'Good evening, gentlemen,' said Inspector Davis. 'Now then, who found the body?'

I explained the circumstances.

'Did it sound like Parker's voice on the telephone, Doctor?'

'Well - I didn't really notice. I just assumed it was him.'

'How long would you say Mr Ackroyd has been dead, Doctor?'

'Half an hour at least.'

'The door was locked on the inside? What about the window?'