A rather untidy porter was polishing the brass bell-push, and Tanner engaged him in conversation. Yes, he remembered a well-dressed old gentleman calling about half-past three on that Monday, three weeks earlier. He would recognise him if he saw him. Yes, he was sure that was his photograph. The gentleman had asked was a Mr Douglas staying in the hotel, and on being answered in the affirmative he had gone up to the latter’s bedroom and remained with him for about half an hour. Then he had left, and that was all the porter knew.

‘And what sort of a man was Mr Douglas?’ Tanner asked.

‘A small man, very small and thin,’ the porter returned. ‘Looked as ’ow a breath of wind would ’ave blown ’im away. Sort of scared too, I thought.’

Tanner pricked up his ears.

‘What was he like in face?’ he asked.

‘ ’E was getting on in years—maybe sixty or more, and ’e ’ad a small, grey goatee beard, and a moustache, and wore spectacles. ’E spoke like an American man and was a bit free with ’is langwidge, damning and cursing about everything.’

At last! Was this the man for whom he and Sergeant Longwell had been searching—the man who had made the fifth set of tracks at Luce Manor, and who had travelled from St Albans to London on the morning after the crime? With thinly veiled eagerness Tanner continued his questions.

‘Who cleans the boots here?’

The porter looked interested.

‘I do,’ he replied, ‘and why that?’