‘Never mind about that! You listen to me!’ said Hemingway. ‘She was stabbed, I tell you, and the man made off. She staggered, and would have fallen, if the Countess with her hadn’t thrown an arm round her. Have you got that? She’d no idea she had been stabbed. The Countess asked her if she was ill, and it says here that she replied that she didn’t know. The Countess asked her if she would take her arm, and she refused. Now, get this, and get it good! She walked on board that steamer, and it wasn’t until she was on it, and it had begun to move, that she fainted! Then, when they started loosening her clothes, they found that there were traces of blood. She died a few minutes later.’

‘Good lord!’ the Sergeant gasped. ‘You mean that you think – you mean that it’s possible –’

‘I mean that Nathaniel Herriard wasn’t stabbed in his bedroom at all,’ said Hemingway. ‘Do you remember that the medical evidence was that death probably followed within a few minutes? Neither of the doctors ever said that death was instantaneous. It wasn’t. After he’d been stabbed, he walked into his room, and locked the door, and that door was never opened again until Ford and Stephen Herriard forced the lock.’

The Sergeant swallowed twice. ‘And Joseph gave himself an alibi!’

‘Joseph gave himself an alibi for the whole time between the locking of that door and the breaking of it open, having already committed the murder.’

‘But when did he do it?’ demanded the Sergeant. ‘Miss Clare went upstairs with him, don’t forget that! He can’t have done it with her looking on!’

‘Get her!’ said Hemingway, shutting the encyclopedia with a snap. ‘You’ll probably find her in the billiard-room with young Stephen.’

The Sergeant did find her there, and returned to the library presently escorting not only Mathilda, but Stephen too. He indicated to Hemingway, by a deprecating gesture, that he had been unable to leave Stephen behind, and cast a reproachful look upon that wholly impervious young man.

‘Look here, Inspector!’ said Stephen, with an edge to his voice, ‘when you’ve quite finished annoying Miss Clare with futile interrogations, perhaps you’ll let me know!’

‘I will,’ promised Hemingway. ‘There’s nothing for you to get hot under the collar about, sir. Since she’s bound to take you into her confidence anyway, I don’t mind you staying here, as long as you behave yourself, and don’t try to waste my time protecting her from the cruel police.’

‘Damn your impudence!’ Stephen said, grinning reluctantly.

‘You sit down, and keep quiet,’ said Hemingway. ‘Now, miss, I’m sorry to bother you again, but there’s something I want you to answer. You’ve told me what happened after you got upstairs to your room on the evening Mr Herriard was murdered: what I want you to tell me now is what happened before you went into your room. As I remember, you stated to Inspector Colwall that you went upstairs with Joseph Herriard?’