While at Grimmauld Place, I continued my efforts to get through to Kreacher. There had to be a key to his loyalty, and I was determined to find it. In retrospect, I should have poisoned the little wretch---nobody'd have suspected me, and between years of Potions classes and plenty of research on the Muggle side, I could have come up with something that no wizard would recognise as poison. Unfortunately, I underestimated him. That, you may be sure, is one thing I'll not do again.