‘What defence? I thought you weren’t arresting me?’

‘It’s a form of words, Dr Hill. As you well know. This isn’t the time or the place for levity. Two women are dead.’ Fielding’s eyes held no promise of warmth. He’d heard she didn’t hold much of a brief for his dark arts; he hadn’t realised how deep her dislike for his work was. And of course, she was ambitious, which could be a hard thing for a female cop to negotiate. Solving these crimes quickly and nailing them on a high-profile offender would do her nothing but good in the eyes of those to whom those things mattered. Was he about to become a scapegoat? It was an unnerving thought. The only option was to pretend he had no idea what was going on.

‘Of course. I apologise. Please, I’m happy to answer your questions. Is this to do with the bus? Only, that was just by chance that occurred to me. I bought more shopping than I intended and I had to get the bus.’

Now it was Fielding’s turn to look baffled.

‘Tony,’ Paula said. ‘All in good time. The first thing I have to ask you is to cast your mind back three Saturdays ago. Can you tell us where you were that Saturday afternoon and evening.’

‘Saturday three weeks ago?’ Theoretically, it should be easy. A day when he had no appointments. A day when he could please himself. But with nothing to differentiate one Saturday from another, how could he say what he had actually done?

‘Bradfield Victoria were playing Chelsea at Stamford Bridge, if that helps.’ Knowing his love for the Vics, Paula had checked the fixture list ahead of the interview.

His face cleared and he smiled. ‘Of course. Ashley Cole conceded a penalty and looked like he was going to cry. I thought about watching it live at the pub, but I didn’t fancy fighting for a seat and all that relentless camaraderie. So I watched the game at home. I had a couple of beers. Then I walked up to the chip shop on Mistle Row and bought cod and chips for my dinner.’

‘Will they remember you?’

‘Three weeks on? I shouldn’t imagine so for a moment. It was busy after the game, I didn’t talk to anyone.’ He gave a hapless little shrug. ‘I didn’t know I was going to need an alibi.’

‘And afterwards?’

‘I went back to the boat.’ He smiled at Fielding. ‘I live on a narrowboat on Minster Basin. I spent the evening alone. I’m finally catching up with Scandinavian noir, so I probably watched a couple of episodes of The Bridge or The Killing then chances are I played Arkham City or Skyrim on my Xbox.’

‘Do you enjoy violent computer games?’ Fielding butted in.