Harper tried not to sigh. “Did you see anyone on a bench, a bit further down?”

“On the bench? Not that I recall.”

Harper brought out a laptop and opened it, turning the screen to face the witness. “I’m going to show you a video of nine people, one of whom is a person of interest. I want you to look at each one carefully, and tell me if any one of them is the woman you saw pushing the stroller.”

The Video Identification Parade Electronic Recording, obtained from the national bureau, showed a head-and-shoulder shot of a dark-haired woman on a grey background, who turned her head from left to right. This was followed by eight more women of a similar age and appearance, who all turned their heads in the same way. Natasha was number seven, her dark hair in oily ropes, cheeks streaked by the ghosts of mascara lines. Durrell stared at her in the same blank way that he stared at the others, showing no sign that he recognised her.

When the tape ended he shook his head.

“I can’t be sure. You know, I thought three and eight were the same person. Were they all supposed to be different?”

Brilliant, thought Harper. She closed the VIPER window and clicked an image open.

“What about this one. Did you see this woman at all?”

He pulled the laptop closer, squinted at the screen.

“Oh, yes, I think that’s her. She looks the type to steal babies, I reckon. She was number four, right?”

Harper took back the laptop. The close-up of Lauren’s face, taken from her driver’s license, stared out at her, unsmiling.

*   *   *

The twenty-four hours she could hold the suspect without charge were almost up. The first interview hadn’t given them much to go on that wasn’t circumstantial. If nothing came out of this second interview, Harper was going to have to let Dowling go. She called down to the custody sergeant to have the suspect brought up from the cells once more.

Natasha and the solicitor, Crace, were already seated when Harper entered the room, carrying a jug of cold water and a stack of plastic cups. It was, if anything, hotter than it had been the last time the three of them had gathered here. Crace plucked at his shirt and fanned himself with a piece of A4.

Harper made the official introductions for the sake of the recording, then turned to Natasha.

“So. We’ve talked about the fact that you and Patrick were in a relationship that ended recently, and that you were angry with him because he didn’t tell you his wife was pregnant. You’ve admitted that you followed Lauren to the valley—”

“I never admitted that. I said I was going for a walk.”

“Watch your step, Sergeant,” said the solicitor.