“Our best guess is that she started to tell the truth, told a bit of it, then panicked,” Sam said. “She was afraid we might try and track down this strange woman who shouted at her in a parking lot. She wouldn’t have known we’d recognize Karen Sanderson instantly from her description of their exchange. There was a risk that Sanderson would tell us Nicki’s car had both its side mirrors when she saw it, and Nicki had just lied to us about having lost one more than a week ago. I think she gave us the granny description of Sanderson to make it less likely that we’d find her.”

“The lie about the missing mirror wasn’t thought through at all,” said Gibbs. “In the CCTV footage, which Nicki knew was what led us to her because Simon and Sam told her, there’s clearly something sticking out of the passenger side of her car where the side mirror ought to be. Of all the stories she could have told, she picked one that was ridiculously easy to prove untrue.”

“She was in a complete state,” said Sam. “I’m surprised she was able to produce any kind of story, though she did calm down once she started to talk about the mirror, funnily enough. It was almost as if the process of creating her lie . . . I don’t know, kind of soothed her.” He turned to Gibbs. “Though I suppose it’s just about possible the mirror thing wasn’t a lie? What if the car accident she described knocked the mirror out of its casing, or container, or whatever—the sticky-out bit that’s there in the CCTV footage? No.” Sam disagreed with himself before anyone else could. “When Simon and I arrived at her house on Tuesday afternoon, the whole of the passenger-side mirror attachment was gone. She’d left the garage door wide open so that we could see it. Obviously she’d done something to break it off between getting picked up on CCTV and us seeing her car. I also think . . . when we got to the house, we bumped into her husband, Adam, who was on his way to pick up the kids. He said Nicki had gone to London—she’d rented a car to get there. Adam was in a tearing rush to get off to school because he’d had to drive her to the car-rental office once she’d found out the trains were messed up . . .” Sam broke off. “Lots of alarm bells were ringing at that point. I’d like to know what was so important to Nicki, immediately after we’d questioned her, that required a rented car and a trip to London, and dragging her husband home early from work.”

“Lying was so important to her,” said Proust. “She’s a compulsive liar.”