Two new figures: a woman and a man. She had long hair, tied back, neither very pale nor very dark. The grey of the footage made colour impossible to determine, and she was bundled in a puffy jacket. She looked almost straight at the camera, without any awareness of it. Alison isolated the image thoughtfully. Khan was a competent amateur sketch artist. It certainly looked like the same person who’d tapped her in the club.

The man with her was about the same height but twice as broad. His long leather coat was split at the shoulder blades, most likely from some particularly energetic part of beating Billy White to death. The camera resolution didn’t show the stains, but that coat must have been gory with blood, and the police were already searching nearby bins and skips for it. The camera only caught a partial profile, but that was enough to pick the man out as strikingly ugly, broad-faced, weak-chinned, heavy-browed. Alison shivered at the sight: a latter-day Karloff in full monster make-up. Surely not hard to track down.

They hadn’t entered via the door though. The police had already gone back through everything still on the camera’s memory. It looked as though the pair had been there for longer than the device could record, or they’d maybe crept in through a window. Except Khan’s place was on the second floor and there was no sign of forced entry except for the door. So had Khan lied, and let them in…? More unknowns awaiting a tidy resolution. Alison had been in the game long enough to know that some mysteries were never resolved. She would, at some point, have to either come to terms with that or go mad. But right now her drive to turn the world into a puzzle, where every piece fit, was what matched her so well to her job.

There wasn’t enough of the man’s face in the footage to run through recognition software, but the girl was another matter. The police would be looking into it, of course, but Alison had a bad habit for an analyst of scaring up her own intel when it suited her. Yet another blot on her record, balanced only by her good results. And if someone was trying to poach Khan, it really was a national security matter.