‘At least it answers a few questions,’ Jonah told the DCS, with an attempt at positivity. ‘I’m pretty sure it was April and her ex-husband who recruited Niall Reakes. I have a strong suspicion that she was doing a lot more, too. My guess is that the whole drugs operation was her brainchild, and under her management. And now that she’s gone, Niall will probably be happy enough pointing the finger at her.’

There was nothing much else for Jonah or the DCS to do about April, except to pass her details to the National Crime Agency and make tracking her down their problem.

Later, in the early evening, Jonah and Lightman had arrived at Issa’s house. They’d come to sit amid his brightly coloured cushions and tell him that his husband hadn’t been a killer after all.

‘Oh my God,’ Issa had said, his hand to his mouth. ‘You’re sure? You’re sure?’

‘Yes,’ Jonah had said. ‘We believe that it was Charlie Ruskin. His friend, apparently.’

‘Charlie?’ Issa asked, his face blank.

‘We think Alex happened on him while he was attacking Louise Reakes,’ Jonah told him. ‘Charlie was masked, and unrecognisable. Alex stepped in to stop him. Louise is now certain that that’s what happened, and that the killer stabbed him and ran.’

Issa was listening to this intently. ‘So … so he tried to save her.’

‘Yes,’ Jonah said, and he added, quietly, ‘I’m so sorry we were so wrong about him.’

Issa’s eyes moved back and forth a few times, as if he was trying to compute all of this. ‘But how did he end up back at her house?’ His voice sounded anguished again. ‘Why didn’t he go for help?’

‘We think it’s because he was very drunk and didn’t realise how badly injured he was,’ Jonah said. ‘And also because he wanted to make sure Louise got home. She says … he put her to bed, and then asked if he could lie down, because he felt unwell. Louise did her best to comfort him, not realising that he was dying.’

Issa’s mouth twisted, and then he nodded. ‘What about – the box? In his car.’

‘It was Charlie’s, not his,’ Lightman said, taking over. ‘We think Charlie had a stroke of good luck. Alex had left his bag at the club, and so Charlie had access to his car keys. He planted the box in Alex’s car at some point during the early hours of the morning, once you’d driven it home and parked up. And then we think he posted the keys through your front door.’