Strike laid the brochure on the desk in front of her. The cover showed a tall modern tower topped by a strange shield-like face in which wind turbines were set like three eyes. The legend read: “Strata SE1, London’s most desirable residential property.”

“See?” said Strike.

His triumphant air was aggravating Robin beyond measure, not least because it seemed so unlike him to gloat about the prospect of borrowed luxury, but before she could respond there was a knock on the glass door behind him.

“Bloody hell,” said Strike in frank astonishment as he opened the door to Shanker, who walked in, clicking his fingers and bringing with him the usual fug of cigarette smoke, cannabis and body odor.

“I was in the area,” said Shanker, unconsciously echoing Eric Wardle. “I’ve found him for you, Bunsen.”

Shanker dropped down onto the mock-leather sofa, legs spread out in front of him, and took out a packet of Mayfairs.

“You’ve found Whittaker?” asked Strike, whose dominant emotion was astonishment that Shanker was awake so early in the morning.

“’Oo else did you ask me to find?” said Shanker, inhaling deeply on his cigarette and clearly enjoying the effect he was creating. “Catford Broadway. Flat over a chip shop. The brass lives with ’im.”

Strike held out his hand and shook Shanker’s. Notwithstanding his gold tooth and the scar that twisted his upper lip, their visitor’s grin was strangely boyish.

“Want a coffee?” Strike asked him.

“Yeah, go on then,” said Shanker, who seemed disposed to bask in his triumph. “All right?” he added cheerfully to Robin.

“Yes, thanks,” she said with a tight smile, returning to the unopened mail.

“Talk about on a roll,” Strike said quietly to Robin while the kettle boiled loudly and an oblivious Shanker smoked and checked texts on his phone. “That’s all three of them in London. Whittaker in Catford, Brockbank in Shoreditch and now we know Laing’s in Elephant and Castle—or he was three months ago.”

She had agreed to it before doing a double take.

“How do we know Laing was in Elephant and Castle?”

Strike tapped the glossy brochure of the Strata on her desk.

“What d’you think I’m showing you that for?”

Robin had no idea what he meant. She looked blankly at the brochure for several seconds before its significance struck her. Panels of silver punctuated the long jagged lines of darkened windows all down the rounded column: this was the background visible behind Laing as he stood on his concrete balcony.

“Oh,” she said weakly.

Strike wasn’t moving in with Elin. She did not know why she was blushing again. Her emotions seemed totally out of control. What on earth was wrong with her? She turned on her swivel chair to concentrate on the post yet again, hiding her face from both men.

“I dunno if I’ve got enough dosh on me to pay you, Shanker,” Strike said, looking through his wallet. “I’ll walk you down to a cashpoint.”

“Fair enough, Bunsen,” said Shanker, leaning over to Robin’s bin to dispose of the ash trickling from his cigarette. “You need ’elp wiv Whittaker, y’know where I am.”