Thus you understand how I know these facts.
"This takes me back to where I was lost in the streets of Valetta and forced to inquire my way.

As luck would have it I saw a man before me, but ere I reached him he was joined by a woman.
"I stood still; in the dusk I heard him say something that gave me a thrill, and as near as I can remember those words were: "'For love of you, Pauline Potter, I have assumed this disguise and become for the present Signor Stucco, the master of Valetta's police.
Now give me orders; tell me how I am to win your favor; how bring to the Strada Mezzodi--' I heard no more, as his voice fell, but presently my ears, sharpened to an intensity, caught a name--it was--'Doctor Chicago.'" "You interest me, professor; please proceed." "Ah! that is all.

I lost track of them and managed to work my way to the hotel in time for dinner.

When that man called you out, I recognized the dim figure I had seen talking with the soft-voiced woman at dusk.

It takes time for me to figure things out, and I must be beyond the range of her voice.