When the novel first sold, I said a few things for the Bookseller announcement that never made the final article, so I'll post them here as I think they offer a bit more of an insight into what the book is about:
"I’m absolutely delighted, and still a little stunned, that Lucy and the amazing team at Sphere and Little, Brown will be launching The Killer You Know. It’s genuinely a dream come true for me. I’ve always been fascinated by the way in which other people’s memories of who you were can affect who you are in the present. I was struck by the idea of a reunion where a recollection of a friend’s jokey remark, made in the baffling heat of adolescence, is seen in a sinister new light. It seemed irresistible to me. Whether for good or bad, you can’t escape the role nostalgia plays in modern culture, and I had a great time exploring that with film podcast host Adeline, and the rest of the book’s characters, as they tumbled into their own pasts. I really look forward to sharing this adventure with readers."