‘You say you were surprised to find the boathouse door unlocked. I have been at the boathouse scores of times, and I never knew it to be locked. Why should it have been locked then?’
‘I lock it, sir,’ the man replied, ‘every night at dusk. Every morning I open it, and it stays open through the day.’
‘And did you lock it last night?’
‘Yes, sir.’
‘About what time?’
‘About 8.00 or 8.30, I should think.’
‘Who else has a key?’
‘No one but Sir William, sir.’
Austin turned to the butler.
‘Do you know where he keeps this key?’