‘Which probably means they share the car,’ Rachel said. ‘Thanks, Sam. I want a warrant to search their house. Can you get that started? We’ll focus on perverting the course of justice for now. I’ll call Sharon, let her know what we’ll need from her.’

Hanging up from Sam, Rachel passed the phone back to Ade and used her own phone to call Sharon.

‘You’re on the way there now?’ Sharon asked, when Rachel had finished updating her.

‘We’re about fifteen minutes away, tops. I’ve asked Sam to start processing a warrant. It won’t be ready by the time we get there, but we’ve got enough to arrest Simon and keep him until we can search the house. I’ve called for back-up to meet me there.’

‘Good work,’ Sharon said. ‘I’ll call Sam now, tell him to go through me with the warrant so I can fast-track it. Keep me updated, okay?’

Simon was alone when Rachel and Ade arrived at the house and seemed genuinely confused when Rachel informed him that he was under arrest.

‘I don’t understand,’ he said, frowning. ‘You think I killed my own brother?’

Rachel had expected him to put up a fight, but the only resistance he gave was to repeatedly ask why he was being arrested.

‘Where’s your wife?’ she asked, as she led him outside to the squad car.

‘You want to arrest Bella too?’ Simon looked even more confused. ‘What’s happened? We haven’t done anything wrong. Is it Adam? Has he put you up to this?’

‘Tell me where I can find Bella,’ Rachel said, shoving him into the back of the waiting squad car.

‘She’s at work,’ Simon said. ‘But she won’t speak to you. She’s in the middle of something important and can’t be disturbed.’

Rachel shut the car door and told the two uniformed officers to take Simon to Brighton police station.

‘Get him processed and start the clock,’ she instructed. ‘I’ll be back as soon as I can to interview him.’

The entrance to Max-Roysten Pharmaceuticals was closed when Ade pulled up outside fifteen minutes later.

‘Doesn’t mean she’s not in there,’ Ade said. ‘Makes sense they’d lock up at nights. I imagine a company like this would be a target for animal rights activists.’

‘MRP prides themselves on not doing animal trials,’ Rachel said, remembering the promotional videos she’d watched the last time she’d been here. She spotted an intercom system in the wall beside the gates. Jumping out, she pressed the button that – she hoped – would connect her with a real person inside the building.

‘Hello?’ A man’s voice, low and gravelly. ‘Who’s there?’

‘Police,’ Rachel said, giving Ade the thumbs up. ‘I need to urgently speak to one of your employees, Bella Gilbert.’

The man gave a wheezy laugh.