"Ah yes. Of course," Sandra said. "You must excuse me. As Mr Wake pointed out earlier, I have a tendency to speak in circles, especially when I'm excited." She took another sip of scotch. "Well. How should I say this." She paused for a moment before brightening. "I suppose the beginning would be a good place to start. In one of my more recent...personal excursions to the far corners of the earth, I came upon a quite remarkable piece of jewelry," Sandra explained. "It was guarded with countless spells, but they had grown weak with time and neglect, and proved little challenge to a wizard as powerful as I am. I seized the jewelry - a pendant, as it was - and almost immediately realized that what I was holding went dar beyond some petty magical item. I realized that in my hand was a piece of a human soul."
She smiled, one that stretched unnaturally far across her face and showed too many teeth. "As you've probably already guessed, what I had found was a horcrux. Excited beyond belief, I immediately apparated back to London, gathered my wits, and contacted Mr. Wake here. With his help, we were able to partially free the soul from the pendant, and were able to find it's identity."
She arched an eyebrow. "Thaor, have you ever heard of Grindelwald?"