‘I know what happened. What I don’t know is why two of my best officers aren’t following procedure.’

‘I was just chasing up his brief.’

‘Outside,’ said Erika, noting that the cameras were still recording their conversation.

When they came out into the corridor, Erika continued, ‘You know Peterson has a grudge against Wilmslow. He's a scumbag, but he has an alibi for the Gregory Munro murder. Your job is to investigate this murder. Not to start bringing people in for anything that takes your fancy.’

‘It didn’t take our fancy, it was…’

‘Just go home, Moss. I’ll sort this out.’

‘But…’

‘Go home. Now!’

‘Yes, boss,’ said Moss. She wiped the sweat off her forehead and walked away, leaving Erika alone in the corridor. The harsh fluorescent light beat down on her.

An hour later, Erika found Peterson in the men’s locker room in the basement of the station. It stank of floor polish and body odour. Peterson was sitting on a row of benches, resting against the lockers. One of the metal doors opposite was dented, and bloodied tissue was bunched around Peterson’s hand.

‘He was just asking to be brought in, boss,’ said Peterson, looking up and seeing her. ‘He barged into the house, knocked Estelle down. He told us to go fuck ourselves.’

‘He’s scum, Peterson. But if I’d arrested everyone who told me to go fuck myself, the prison system would go into meltdown.’

There were no windows, and the lights were all off apart from the ones above a row of sinks, casting an eerie glow over the room. Erika felt exposed in her thin summer dress, her dangly silver earrings slapping against her cheek. She crossed her arms over her chest.

‘So what exactly did you arrest him for, Peterson?’

‘He had dodgy cigarettes he was planning to sell!’

‘And what proof do we have he was going to sell them?’

‘Come on, boss. There were thousands!’

‘And if he was intending to sell them, what part of our murder investigation does that come under?’ asked Erika.

‘Boss, Wilmslow is out on licence,’ said Peterson. ‘It’s got to be worth something. We still don’t know if he was responsible for the death of Gregory Munro. This will give us time to look into it more.’

‘He’s not responsible for the death of Gregory Munro!’ snapped Erika.

‘We don’t know that, boss. His alibi is from his sister and mother, who…’

Erika went to the sink and ran the cold water. She splashed her face, and scooped some up in her hand and took a long drink. She turned off the tap and wiped her mouth with a paper towel.

‘Peterson…’

‘What?’

‘Gary Wilmslow is under investigation for the production and distribution of child pornography. He’s potentially a key player in a massive underground paedophile network. He’s under covert police surveillance. Because of this, they know he didn’t kill Gregory Munro. His alibi is sound.’

Peterson looked up at her in shock. ‘You’re serious?’

‘Yes, I’m serious, and I shouldn’t be bloody telling you this.’

Peterson slumped forward and put his head in his hands.

‘You cannot let idiots like Wilmslow get under your skin. You know his type. He knows how to push buttons. He’s been doing it from an early age. I thought you were more intelligent than that. Personal vendettas cloud judgement.’

‘How close are they to making an arrest?’ Peterson croaked, almost fighting back tears.

‘I don’t know. Marsh informed me a couple of days ago when I wanted to go after Wilmslow. It’s called Operation Hemslow. They think there’s a factory pressing the DVDs and there’s hundreds of hours of… footage being produced and uploaded to the net.’

The word hung in the air. Peterson leaned back and pressed his palms to his eyes.

‘No, no, no, no…’ he said. Erika was shocked at how he was taking this. He wasn’t trying to shift blame or defend himself. He pulled his hands away from his eyes. ‘What happens now?’

‘Ignorance isn’t an excuse, and you’re bloody stupid… But you didn’t know about Wilmslow. You were doing your job, even if you did do it cack-handedly. You’re lucky Wilmslow started it in the interview room. I’ll tell Marsh I’ve given you the mother of all bollockings.’

He looked up at her, surprised at her even tone.