Sydney Gardens was the oldest park in Bath, famous for its replica Roman temple of Minerva. It was also notorious for cottagers – you only had to step one pace off the path to see a young man, nicely dressed, standing sheepishly in the bushes, a hopeful smile on his face. Parents frog-marched their children past the vicinity of the toilets, talking loudly to distract their attention, and dog-walkers regularly came to the local vets with dogs choking on used condoms scavenged from the undergrowth. A railway line ran through the park – police teams had thoroughly searched it already, as it wasn’t unknown for bodies to be pulverized and scattered by a speeding train to the point at which they seemed to have disappeared altogether. Now, however, the search teams weren’t looking for a body. They were looking for clues about Lorne’s journey from town to the place she’d been killed.

Zoë and Ben walked down the canal path not speaking. From time to time one of them would stop and peer into the bushes on the right, or down into the impenetrable canal water, hoping to catch sight of something significant that the teams had missed. About a quarter of a mile back into town Zoë stopped at a small gate in a wall. The woody branches of a wisteria hung over it, the pendulous purple racemes just beginning to open. The gate led into Sydney Gardens. It was probably the place Lorne had got on to the towpath. Zoë and Ben stood opposite each other, faces lowered, considering the patch of mud between their feet.

‘Is it what was on her shoes?’ he asked.

‘It’s the same colour.’

Ben raised his head and scanned the path – the puddles that straddled the gravel. It had rained yesterday, but the sun was drying it now. ‘A lot of places in Bath have mud this colour. It’s the limestone in the earth.’

Zoë eyed the puddles. She was thinking about the shoes. Ballet pumps. Unsuitable for walking, really, but all the girls wore them these days.