‘It’s Bailey Pike speaking. I’d like to talk to Mr Knight please.’

‘Just putting you through.’

The familiar strands of Beethoven’s ‘Moonlight Sonata’ played for a few seconds and then Frank came on the line.

‘Made any progress?’

‘It’s not Dylan,’ she said. ‘He wasn’t here when Sharon was murdered. He had a day off. He did a last-minute shift swap with another prison officer. And if he didn’t kill Sharon then that means he probably didn’t kill the others either.’

Frank was quiet for a few moments.

‘So all that stuff with Sharon blackmailing him…?’

‘Mistaken conjecture. I was barking up the wrong tree. She was just in the wrong place at the wrong time.’

‘You realise this puts you right back at square one,’ he said. ‘First, there was the Hairdresser and that didn’t come to anything. And now the Dylan angle has fallen through. It feels to me like you’re grasping at straws. Things aren’t looking too promising, are they, Bailey?’

‘Not quite.’

‘How’s that then?’

She glanced around and tucked herself further into the phone booth.

‘I was looking at Dylan’s rota and it got me thinking about the dates. Sharon was murdered on the twenty-third of June. Right?’

‘Yeah that’s right.’

‘Go back sixteen days before that to the seventh of June – that was when Natalie was murdered. Go back a further sixteen days and we’re on the twenty-second of May – that was when Poodle got murdered. And go back sixteen more days and it’s the sixth of May – that was when Alice was murdered.’

‘Hmm… Every sixteen days, huh? Interesting. No one else spotted that.’

‘I’m angry with myself that I didn’t spot it earlier, but then time passes strangely in here – you kind of lose track of it. And also it’s not as if sixteen days is an immediately obvious pattern to notice.’

‘Is it connected to the rota?’

‘Not that I can ascertain. At least, I couldn’t make out any clear correlation between the dates of the murders, the locations of the murders and the shift patterns of the prison officers.’

He sighed. ‘So the upshot of all this is that you still don’t have anything.’

‘The whole reason I’m mentioning it is because we now know when the next murder is due to take place.’

‘If there is a next murder. If the killer sticks to this pattern.’

‘The ninth of July,’ she said. ‘That’s when it’s going to happen. In five days’ time.’

‘A date by itself is not enough to justify taking any kind of action. You need to provide me with—’

‘Something solid. Yeah I know.’

Chapter 87

No sooner had she got back to her cell than Bailey turned around to encounter the gang filing through the door, crowding into the small room. Toni. Muscles. Rong. Keisha. No sign of Poppy. She hadn’t noticed them hanging around outside, but then she’d been so deep in thought about the significance of the sixteen-day pattern that she hadn’t really been paying attention to anything else.