“Thanks very much,” said Strike.

As he turned up Mrs. Laing’s drive he noticed, out of the corner of his eye, that the old man was still standing on the spot, watching him, in spite of the collie trying to tug him downhill.

Mrs. Laing’s bungalow looked clean and respectable. Stone animals of Disneyesque cuteness littered her lawn and peeped out from her flowerbeds. The front door lay at the side of the building, in shadow. Only as he raised his hand to the doorknocker did it occur to Strike that he might, within seconds, come face to face with Donald Laing.

For a whole minute after he knocked, nothing happened except that the elderly dog walker retraced his steps and stood at Mrs. Laing’s gate, unabashedly staring. Strike suspected that the man regretted giving out his neighbor’s address and was checking that the large stranger meant the woman no harm, but he was wrong.

“She’s in,” he called to Strike, who was deliberating as to whether to try again. “But she’s wud.”

“She’s what?” Strike called back as he knocked for a second time.

“Wud. Doolally.”

The dog walker took a few steps down the drive towards Strike.

“Demented,” he translated for the Englishman.

“Ah,” said Strike.

The door opened, revealing a tiny, wizened, sallow-faced old woman wearing a deep blue dressing gown. She glared up at Strike with a kind of unfocused malevolence. There were several stiff whiskers growing out of her chin.

“Mrs. Laing?”

She said nothing, but peered at him out of eyes that he knew, bloodshot and faded though they were, must have been beady and ferret-like in their day.

“Mrs. Laing, I’m looking for your son Donald.”

“No,” she said, with surprising vehemence. “No.”

She retreated and slammed the door.

“Bugger,” said Strike under his breath, which made him think of Robin. She would almost certainly have been better than him at charming the little old woman. Slowly he turned, wondering whether there was anyone else in Melrose who might help—he had definitely seen other Laings listed on 192.com—and found himself face to face with the dog walker, who had proceeded all the way down the drive to meet him and was looking cautiously excited.

“You’re the detective,” he said. “You’re the detective that put her son away.”

Strike was astonished. He could not imagine how he was recognizable to an elderly Scottish man whom he had never met before. His so-called fame was of a very low order when it came to being identified by strangers. He walked the streets of London daily without anyone caring who he was, and unless somebody met him or heard his name in the context of an investigation, was rarely associated with the newspaper stories about his successful cases.

“Aye, you did!” said the elderly man, his excitement rising. “My wife and I are friends of Margaret Bunyan’s.” And in the face of Strike’s mystification he elaborated: “Rhona’s mother.”

It took a few seconds for Strike’s capacious memory to render up the information that Laing’s wife, the young woman whom he had discovered tied to the bed beneath the bloodstained sheet, had been called Rhona.