The Case of the Sharp-Eyed Jeweller

Part 4

She put her handbag down on the counter and, taking a little paper packet out of it, she put that down beside her bag, she used her left hand to do this but, strangely enough, she has not shown herself left-handed in anything that she had done before.
I opened the packet and found inside it a piece of cheap jwellery-a filigree brooch with an imitation turquoise stone, worth about thirty shillings.
‘ Could you mend this for me ?’ she asked, showing me the broken pin of the brooch.
‘ I am sorry, madam,’  cartier's does not do repairs.’
‘Thank you,’ she said. Then, as if by accident, her arm somehow swept against the paper in which the brooch had been wrapped, and his fell to the floor on my side of the counter. I say ‘as if by accident’ because, in fact, it was no accept at all. It was a cunning trick.
I realised this as I bent down to pick up the paper. All that facts suddenly came together in my head, and I knew what had happened to the flower ring. All the things that I had noticed joined to form a single picture, and that picture showed me all that I wanted to know.
I put the brooch back into its paper into its paper wrapping and handed it to her. She put it into her handbag, using her right hand to do this, and then turned to leave the shop.

Will see you again in another part 〽️