Atkinson said, “So she’s running toward the water, right? For what? To drown herself?”

“What else could it be?” asked Eddie.

“Are we thinking that A wanted to kill herself, and B was trying to help her do it?”

Joanna said, “B would never do that.” She blurted it, too fast and too loud. Both of the men looked at her, baffled. “I mean, the evidence doesn’t point to that. It makes no sense for that to be the reason. And let’s say she did go into the water to drown herself. There would be a body washed up by now.”

“Not necessarily,” said Atkinson. “It can take days, months, years. If she caught a riptide, then the body might never wash up.” He gave her a look that said, “Are you feeling okay?”

“What we do know for sure,” said Eddie, “is that after this, A isn’t seen again on any cameras we can find. She ran in the direction of the sea. And she never came back.”

They paused for a second to take this in.

“What about B?” said Jo. “You say she got on a train to Edinburgh. Can we track her from there?”

Eddie said, “We’re still looking. I’ll let you know the moment I find something.”

After Eddie left the room, Atkinson and Harper studied the laptop screen, where the child on camera, now completely alone, was fiddling with something on the ground. “What is that?” said Jo.

“Her handbag. That’s what the kid was found with.”

“Where is it now?”

“B has it. The police gave it to her, assumed it belonged to her. But Constance A is the one who carried it to the seafront.”

Harper shook her head. “I can’t understand how they missed that. I’ve read the report. B told the social worker that the kid must have run off carrying it. That child can barely pick it up.”

“If she’d stopped B then, or simply asked a few more questions, none of this would be happening.”

“That’s a bit harsh, boss. Gregor Franks would still have been floating unconscious in his bath, whether or not they’d been apprehended at that point by Social Services.”

Harper could feel her professionalism slipping. She realized she hadn’t been considering the terrible attack on Franks; she was only thinking about Ruby, about the trouble she was in and how she might be helped to get out of it. She told herself to focus on the task at hand. It shouldn’t have mattered that she had connections to any person in this case; she should be able to do her job without prejudice, for the sake of equal justice for all. But at the same time, she already knew what she was going to do, and it wasn’t the most sensible plan.