Strike could tell, by the almost perceptible heaviness that seemed to be descending upon Bristow as he walked, that they were approaching his offices.

‘I’m having difficulty contacting a couple of useful witnesses, John. Is there any chance you’d be able to put me in touch with Guy Somé? His people don’t seem keen on letting anyone near him.’

‘I can try. I’ll call him this afternoon. He adored Lula; he ought to want to help.’

‘And there’s Lula’s birth mother, too.’

‘Oh yes,’ sighed Bristow. ‘I’ve got her details somewhere. She’s a dreadful woman.’

‘Have you met her?’

‘No, I’m going on what Lula told me, and everything that was in the papers. Lula was determined to find out where she came from, and I think Duffield was encouraging her – I strongly suspect him of leaking the story to the press, though she always denied that… Anyway, she managed to track her down, this Higson woman, who told her that her father was an African student. I don’t know whether that was true or not. It was certainly what Lula wanted to hear. Her imagination ran wild: I think she had visions of herself being the long-lost daughter of a high-ranking politician, or a tribal princess.’

‘But she never traced her father?’

‘I don’t know, but,’ said Bristow, displaying his usual enthusiasm for any line of inquiry that might explain the black man caught on film near her flat, ‘I’d have been the last person she’d have told if she did.’

‘Why?’

‘Because we’d had some pretty nasty rows about the whole business. My mother had just been diagnosed with uterine cancer when Lula went searching for Marlene Higson. I told Lula that she could hardly have chosen a more insensitive moment to start tracing her roots, but she – well, frankly, she had tunnel vision where her own whims were concerned. We loved each other,’ said Bristow, running a weary hand over his face, ‘but the age difference got in the way. I’m sure she tried to look for her father, though, because that was what she wanted more than anything: to find her black roots, to find that sense of identity.’

‘Was she still in contact with Marlene Higson when she died?’

‘Intermittently. I had the feeling that Lula was trying to cut the connection. Higson’s a ghastly person; shamelessly mercenary. She sold her story to anyone who would pay, which, unfortunately, was a lot of people. My mother was devastated by the whole business.’

‘There are a couple of other things I wanted to ask you.’

The lawyer slowed down willingly.

‘When you visited Lula at her flat that morning, to return her contract with Somé, did you happen to see anyone who looked like they might have been from a security firm? There to check the alarms?’

‘Like a repairman?’

‘Or an electrician. Maybe in overalls?’