‘Ah! a gold tooth.’

‘Exactly. That’s really the crux of the matter.’

Poirot nodded his head several times.

‘I begin to comprehend. Go on.’

‘Well, as I say. I just noticed the fellow. I was travelling, by the way, to New York. Six months later I was in Los Angeles, and I noticed the fellow again. Don’t know why I should have-but I did. Still, nothing in that.’

‘Continue.’

‘A month afterwards I had occasion to go to Seattle, and shortly after I got there who should I see but my friend again,only this time he wore a beard.’

‘Distinctly curious.’

‘Wasn’t it? Of course I didn’t fancy it had anything to do with me at that time, but when I saw the man again in Los Angeles, beardless, in Chicago with a moustache and different eyebrows and in a mountain village disguised as a hobo-well, I began to wonder.’

‘Naturally.’

‘And at last-well, it seemed odd-but not a doubt about it. I was being what you call shadowed.’

‘Most remarkable.’ 

‘Wasn’t it? After that I made sure of it. Wherever I was, there, somewhere near at hand, was my shadow made up in different disguises. Fortunately, owing to the gold tooth, I could always spot him.’

‘Ah! that gold tooth, it was a very fortunate occurrence.’

‘It was.’

‘Pardon me, M. Martin, but did you never speak to the man? Question him as to the reason of his persistent shadowing?’

‘No, I didn’t.’ The actor hesitated. ‘I thought of doing so once or twice, but I always decided against it. It seemed to me that I should merely put the fellow on his guard and learn nothing. Possibly once they had discovered that I had spotted him, they would have put someone else on my track-someone whom I might not recognize.’

‘En effet…someone without that useful gold tooth.’

‘Exactly. I may have been wrong-but that’s how I figured it out.’