She couldn’t conceive of Ruby hurting anyone. Certainly not doing something like what had happened to Franks. But then, did she really know Ruby at all? She hadn’t seen her for so long. What the hell was she doing with that child?

“So,” said Harper, “we know the movements of Constance B, after she left Sheffield and up to the point where she gets on the Edinburgh train with the kid. What about Constance A?”

“After she left the New Park in the afternoon, she got a direct train, with the girl, from Sheffield to Cleethorpes. It stopped at Grimsby at 15:37,” said Eddie. “I’m wondering if they were supposed to meet up at that point and travel to Cleethorpes together. Or if A was going to hand the kid over to B and travel to Cleethorpes alone.”

“B only had a ticket to Grimsby, which backs up that theory,” said Atkinson. “She had to buy another ticket to get to Cleethorpes. I suggest the plan didn’t take into account the trains being delayed. Looks to me like the rendezvous should have happened at Grimsby station, and would have if B’s train had been on time.”

“I still don’t get why A would abandon the kid, though,” said Eddie. “Why couldn’t she have just waited a few more minutes if she was planning to hand her over to B all along?”

“I found footage of what happened at the seafront,” said Eddie. “Watch this.” He set a laptop on the table in front of them.

The woman in the image was waiting with the child. The camera picture was hazy, all in shades of green, darkening as the light drained from the day. Shot from above, both figures were foreshortened, but it was definitely the same pair that had traveled from Sheffield.

“They’re there for quite a while. I’ll forward it a bit.”

The sped-up Constance kept glancing at her wristwatch and staring off-camera in the direction of the sea. “She must be waiting for B,” said Jo. “But what’s she planning to do?”

“You’ll see,” said Eddie.

On the screen, Constance held the little girl close, pressing her face into Leonie’s hair. Then she put the child down, took a step away. Looked back at the little girl. Her hand went to her mouth.

Eddie said, “She’s hesitating. She doesn’t want to do it.”

“Do what?” said Atkinson.

Then the child toddled toward a shop window, and at the same time the woman disappeared from the shot.

“Where’s she gone?”

“I can slow it down slightly. Hang on.”

The split second in which the woman disappeared was like watching a sprinter shooting out of the blocks. One last look at the kid and she crouched, then ran in the direction of the sea.

“Is there no camera that covers the beach?”

Eddie shook his head no.