‘Where do you work?’

‘I teach history at the Harris Academy in St John’s Wood. I usually go there by bike. It’s about twenty minutes away. Otherwise, I take the tube from Paddington.’

‘Did you go by tube or bike yesterday?’

‘I took the bike. Olivia saw me leave. We spoke a few words. Nothing of any interest.’

‘Your daughter went to the theatre with your wife, but you didn’t,’ Hawthorne said. I’d told him that I’d met Olivia at the party and that she was a friend of Sky Palmer, the actress who played Nurse Plimpton.

‘That’s right.’

‘Why was that?’

Arthur shrugged as if the answer was obvious. ‘I don’t much like theatre. Anyway, Harriet preferred it if I didn’t come. I have a slight problem with asthma and she used to say the sound of my breathing put her off.’

‘So when was the last time you spoke to your wife?’

‘I called her from school. That was a few minutes before ten o’clock, between lessons. She was already up and at work by then.’

‘How did you know?’ I asked.

Hawthorne wasn’t pleased. He never liked it when I chipped in and perhaps it was a bit inappropriate, me being the main suspect.

‘I FaceTimed,’ Arthur replied. ‘I could see her. She was sitting in her study.’ He pointed at a door leading off from the kitchen. ‘It’s the dining room, but we never used it for eating. We never had guests. That was where she worked.’

‘Can we see it?’

‘If you want.’ He got up, leaving his coffee behind.

Harriet’s office could be accessed directly from both the kitchen and the corridor: there was a second door opposite Olivia’s bedroom. It was a rectangular space, running to the bay window I had seen as I approached the house. Most of the area was dominated by a dining table, which was evidently where she had worked. It was piled up with notepads, files, newspaper clippings and theatre programmes. There were about a dozen pens spilling out of a Book of Mormon mug, a half-empty bottle of wine and a glass decorated with a lipstick smear that must have been made by Harriet, the last mark she had left in this world. I glanced at the bookshelves. I wasn’t surprised to see play texts, actors’ and directors’ biographies, histories of different theatres. She also had a strong interest in crime and I remembered her telling me that it was something she had written about. I hadn’t realised she had meant books, though. I noticed three of them spread out on the table with her name on the covers, placed there as if to impress.

‘This is her room,’ Arthur said. ‘It doesn’t get enough light … she was never happy with it. That’s the trouble having a house that’s north-facing.’ He looked around him. ‘Your lot have taken her computer and some of her papers,’ he went on. ‘But otherwise this is more or less how she left it.’