It was a frosty day. John took his dog Max for a walk in the woods behind his house. After a rainy week with thunderstorms, the temperature had dropped below zero, leaving a silver coating of ice crystals on the leaves. It was 1988 and John had retired from his job as a police officer in northern Sweden. This morning, the cold sharpened his edges. The dog was obsessively sticking his nose into what looked like a stack of hay. He called out for Max. But when the dog refused to listen, John walked over.