Sasha folded her arms. ‘What’s the bad news?’

‘The CCTV in the driver’s compartment of the train was faulty.’

‘You’re joking. And what’s the bad news?’

‘That’s the platform CCTV.’ He nodded at the printouts and she picked them up, frowning at the murky images of a figure wearing a long overcoat, wide trousers, trainers and a floppy hat, walking stiffly to the extreme bottom of the time-stamped image, and staying there. ‘Our mystery person is of average height, maybe a touch smaller, I’d say five foot eight, but the face is hidden under the brim of the hat.’

‘Clever,’ said Ajay, as Sasha shuffled through the photos. ‘They’re standing in the only place on the entire platform they’re not able to be seen clearly.’

‘Wait,’ Sasha told Craig. ‘There’s a camera in the ticket office, we can get a much clearer shot from that.’

‘There is, but the side gate that leads directly from the car park onto the platform is left open late at night when the ticket office is unattended. Our suspect – or witness – used that instead.’

‘I can’t see a walking stick or a cattle prod.’

‘A cattle prod?’ asked Craig in surprise.

‘Look, the arms are pressed straight down at the sides.’ Ajay pointed at the figure. ‘I bet they’re holding it against their body underneath their coat.’

‘And the confrontation?’ Sasha asked Craig in exasperation.

‘Happens off-screen, directly below the camera.’

‘Fiddlesticks,’ she said, annoyed.

‘Careful with the language, Mrs Dawson,’ said Ajay drily and lifted himself from the edge of the desk. Craig and Sasha saw the wet stain on the seat of Ajay’s pristinely pressed trousers, but she shook her head tightly at the DC. Please don’t tell him.

‘I’ll come and look at that footage in a minute,’ she said quickly. ‘We’ll go through it as many times as it takes. There must be something we can use.’

‘By the way,’ smirked Craig, ‘there’s someone downstairs who wants to speak to a senior officer about Andrew Dean.’

‘Who?’

He kept his voice down. ‘That guy Abs, the one we were talking about.’

Lolly’s head popped up above her monitor. ‘Abs is here?’

‘Do we know why?’ Sasha asked Craig, but he shrugged. ‘Okay, let’s put him in one of the offices downstairs.’

Sasha fumbled her feet into her brogues, stamping her heels so she didn’t have to untie the laces. She mopped up the last of the juice, cleaned her hands with wet wipes, then took the stairs to the ground floor. Outside the room, she found the celebrity surrounded by police and civilian staff.

He was chatting and laughing as he moved from person to person, the bracelets on his wrists jangling loudly as he shook hands and posed good-naturedly for selfies. Sasha made a mental note to remind everybody by email not to put those photos up on social media.

Lolly Chambers stood at the front of the huddle of people, looking up at Abs with the focused excitement of a small child waiting at an ice-cream van.