‘Did you want her dead, after what she’d done to you?’ Ravi asked.

‘Of course I did,’ Nat said darkly. ‘Of course I wanted her gone. I skipped two days of school because I was so upset. And when I went back on the Wednesday, everyone was looking at me, laughing at me. I was crying in the corridor and Andie walked by and called me a slut. I was so angry that I left her a nice little note in her locker. I was too scared to ever say anything to her face.’

Pip glanced sideways at Ravi, at his tensed jaw and furrowed brows, and she knew he’d picked up on it too.

‘A note?’ he said. ‘Was it a . . . was it a threatening note?’

‘Of course it was a threatening note,’ Nat laughed. ‘You stupid bitch, I’m going to kill you , something like that. Sal got there first, though.’

‘Maybe he didn’t,’ Pip said.

Nat turned and looked Pip in the face. Then she burst into loud and forced laughter, a mist of spit landing on Pip’s cheek.

‘Oh, this is too good,’ she hooted. ‘Are you asking me whether I killed Andie Bell? I had the motive, right, that’s what you’re thinking? You want my fucking alibi?’ She laughed cruelly.

Pip didn’t say anything. Her mouth was filling uncomfortably with saliva but she didn’t swallow. She didn’t want to move at all. She felt Ravi brushing against her shoulder, his hand skimming just past hers, disturbing the air around it.

Nat leaned towards them. ‘I didn’t have any friends left because of Andie Bell. I had no place to be on that Friday night. I was in playing Scrabble with my parents and my sister-in-law, tucked in by eleven. Sorry to disappoint you.’

Pip didn’t have time to swallow. ‘And where was your brother? If his wife was home with you?’

‘He’s a suspect too, is he?’ Her voice darkened with a growl. ‘Naomi must have been talking then. He was out at the pub drinking with his cop friends that night.’

‘He’s a police officer?’ Ravi said.

‘Just finished his training that year. So yeah, no murderers in this house, I’m afraid. Now fuck off, and tell Naomi to fuck off too.’

Nat stepped back and kicked the door shut in their faces.

Pip watched the door vibrating in its frame, her eyes so transfixed that it looked for a moment like the very particles of air were rippling from the slam. She shook her head and turned to Ravi.

‘Let’s go,’ he said gently.

Back in the car, Pip allowed herself to just breathe for a few slow seconds, to arrange the haze of her thoughts into actual words.

Ravi found his first: ‘Am I in trouble for, well, literally tripping into the interrogation. I heard raised voices and –’

‘No.’ Pip looked at him and couldn’t help but smile. ‘We’re lucky you did. She only talked because you were there.’

He sat up a little straighter in his seat, his hair crushed against the roof of the car. ‘So the death threat that journalist told you about,’ he said.

‘Came from Nat,’ Pip finished, turning the key in the ignition.

She pulled the car off the kerb and drove about twenty feet up the road, out of sight of the Da Silva house, before stopping again and reaching for her phone.

‘What are you doing?’

‘Nat said her brother is a police officer.’ She thumbed on to the browser app and started typing her search. ‘Let’s look him up.’

It came up as the first item when she searched: Thames Valley Police Daniel da Silva. A page on the national police website, telling her that PC Daniel da Silva was a constable on the local policing team covering Little Kilton. A quick check to his LinkedIn profile said he had been so since the end of 2011.

‘Hey, I know him,’ Ravi said, leaning over her shoulder, jabbing his finger at the picture of Daniel.

‘You do?’

‘Yeah. Back when I started asking questions about Sal, he was the officer who told me to give it up, that my brother was guilty beyond doubt. He does not like me.’ Ravi’s hand crept up to the back of his head, losing his fingers in his dark hair. ‘Last summer, I was sitting on the tables outside the cafe. This guy –’ he gestured to the photo of Daniel – ‘made me move along, said I was “loitering”. Funny that he didn’t think all the other people outside were loitering, just the brown kid with the murderer for a brother.’

‘What a contemptible arsehole,’ she said. ‘And he shut down all your questions about Sal?’

Ravi nodded.

‘He’s been a police officer in Kilton since just before Andie disappeared.’ Pip stared down at her phone into Daniel’s forever-smiling snapshot face. ‘Ravi, if someone did frame Sal and make his death look like suicide, wouldn’t it be easier for someone with knowledge of police procedure?’

‘That it would, Sarge,’ he said. ‘And there’s the rumour that Andie slept with him when she was fifteen, which is what she used to blackmail Nat out of the play.’

‘Yes, and what if they started up again later, after Daniel was married and Andie was in her final year? He could be the secret older guy.’

‘What about Nat?’ he said. ‘I sort of want to believe her when she says she was home with her parents that night because she’d lost all her friends. But . . . she’s also proven to be violent.’ He weighed up his hands in a conceptual see-saw. ‘And there’s certainly motive. Maybe a brother-and-sister killer tag team?’