PROLOGUE A Friday in November It happened every year, was almost a ritual. And this was his eighty-second birthday. When, as usual, the flower was delivered, he took off the wrapping paper and then picked up the telephone to call Detective Superintendent Morell who, when he retired, had moved to Lake Siljan in Dalarna. They were not only the same age, they had been born on the same day—which was something of an irony under the circumstances. The old policeman was sitting with his coffee, waiting, expecting the call. “It arrived.” “What is it this year?” “I don’t know what kind it is. I’ll have to get someone to tell me what it is. It’s white.” “No letter, I suppose.” “Just the flower. The frame is the same kind as last year. One of those do-it-yourself ones.” “Postmark?” “Stockholm.” “Handwriting?” “Same as always, all in capitals. Upright, neat lettering.” With that, the subject was exhausted, and not another word was exchanged for almost a minute. The retired policeman leaned back in his kitchen chair and drew on his pipe. He knew he was no longer expected to come up with a pithy comment or any sharp question which would shed a new light on the case. Those days had long since passed, and the exchange between the two men seemed like a ritual attaching to a mystery which no-one else in the whole world had the least interest in unravelling.
The Latin name was Leptospermum (Myrtaceae) rubinette. It was a plant about four inches high with small, heather-like foliage and a white flower with five petals about one inch across. The plant was native to the Australian bush and uplands, where it was to be found among tussocks of grass. There it was called Desert Snow. Someone at the botanical gardens in Uppsala would later confirm that it was a plant seldom cultivated in Sweden. The botanist wrote in her report that it was related to the tea tree and that it was sometimes confused with its more common cousin Leptospermum scoparium, which grew in abundance in New...