Leanne was swallowed into the yawning mouth of a tunnel, and the echo of her Doc Martens hitting the flagstones followed her along the narrow forty-foot walkway. Grateful to emerge into the sunlight, she blinked as she recognised the stark silhouettes of two Victorian warehouses in the distance. What would have been a ten-minute drive from the marina had taken over half an hour, but she thought it would appear less conspicuous arriving on foot. If asked, she could say she had been passing Karin Gallagher’s apartment by chance.

The converted warehouses were gargantuan relics of a bygone age and had multiple entrances. Leanne followed the Perspex signs screwed to ancient brick until she came up against the entry system that corresponded with the apartment number she had noted from Declan’s file. Alongside the buzzer for each apartment was a name, but Karin’s wasn’t one of them.

Wondering if she had confused the warehouse for its twin next door, Leanne went to turn away, but the name on the label that should have been Karin’s struck a chord. Declan’s sister had a flatmate, and her name had been on the email printout Frankie had shown her. McCulloch. Leanne rang the intercom.

‘Hello?’

The voice was that of a woman around Leanne’s age and, although it was hard to discern the accent from the pithy greeting, Leanne didn’t think the speaker was from Northern Ireland. Karin had left home when she was eighteen and, according to the internet, had backpacked around the world before settling down in Sedgefield. She was thirty-two now, but it was unlikely that she had lost her accent completely. It had to be the flatmate, about whom Leanne had no information at all beyond her name.

‘Is that Beth McCulloch?’

‘Who are you?’

‘My name is Leanne. I was hoping for a chat,’ Leanne said, hedging her bets that she would get further by asking for an interview with Beth rather than Karin.

‘A chat about what?’

‘I’m from the Cheshire Courier and—’

‘No, thanks.’

With a distinct click, the connection was cut. Leanne pushed her luck and pressed the buzzer again, but there was no response. She stared at the intercom, her mouth twisting as she considered her options. She hadn’t expected it to be easy, but never mind. It was a nice day. She could wait.

There was a bench next to the canal with a view of the flight of locks that rose up towards Sedgefield town centre, but Leanne turned her back on the scene and perched on a low wall. With one eye on the entry to Karin and Beth’s apartment, she opened up the internet browser on her phone and began searching for images of the two flatmates to while away her time.