"The Dark Lord once suspected Greyback of defection and sent me, along with Lucius Malfoy, to keep an eye on him while he was there,’ he answered. "I had forgotten about it until you mentioned you had seen him in Glasgow. His family had a couple houses throughout the UK. I recall his house, but I do not know exactly which street it is on. We had tracked him using one of his belongings. It was after your fifth year.’