‘Is he, though?’ Alleyn muttered, more to himself than to Coombe. ‘She promised me she wouldn’t leave the pub. I’ll have to talk to Miss Emily.’ He looked at Coombe. ‘This is going to be tricky,’ he said. ‘If your theory’s the right one, and at this stage it looks healthy enough, do we assume that the stone-chucker, wire-stretcher, composite letterwriter, dumper of green lady and telephonist are one and the same person and that this person is also the murderer of Miss Cost?’

‘That’s what I reckon. I know you oughtn’t to get stuck on a theory. I know that. But unless we find something that cuts dead across it – ’

‘You’ll find that all right,’ Alleyn said. ‘Miss Pride, you may remember, is convinced that the ringer-up was Miss Cost.’

Coombe thought this over and then said, well, all right, he knew that, but Miss Pride might be mistaken. Alleyn said Miss Pride had as sharp a perception for the human voice as was possible for the human ear. ‘She’s an expert,’ he said. ‘If I wanted an expert witness in phonetics I’d put Miss Pride in the box.’

‘Well, all right, if you tell me so. So where does that get us? Does she reckon Miss Cost was behind all the attacks?’

‘I think so.’

‘Conspiracy, like?’

‘Sort of.’

Coombe stared ahead of him for a moment or two. ‘So where does that get us?’ he repeated.

‘For my part,’ Alleyn said, ‘it gets me rather quicker than I fancy, to Wally Trehern and his papa.’

Coombe said with some satisfaction that this, at any rate, made sense. If Wally had been gingered up to make the attacks, who more likely than Wally to mistake Miss Cost for Miss Pride and drop the rock on the umbrella?

‘Could Wally rig a trip-wire? You said it was a workman-like job.’

‘His old man could,’ said Coombe.

‘Which certainly makes sense. What about this padlocked cage over the slot-machine? Is it ever used?’

Coombe made an exasperated noise. ‘That was her doing,’ he said. ‘She used to make a great to-do about courting couples. Very hot, she used to get: always lodging complaints and saying we ought to do something about it. Disgusting. Desecration and all that. Well, what could I do? Put Pender on the job all day and half the night, dodging about the rocks? It couldn’t be avoided and I told her so. We put this cage over to pacify her.’

‘Is it never locked?’

‘It’s supposed to be operated by the hotel at eight o’clock, morning and evening. In the summer that is. But a lot of their customers like to stroll along to the Spring of a summer’s evening. Accordingly, it is not kept up very consistently.’