‘You’re kidding!’ said Lottie, putting a small, immaculately manicured hand up to her small mouth.

‘Afraid not,’ said Moss.

‘I just can’t imagine someone breaking into my flat, let alone someone doing it several times to learn things about me…’

Moss pulled out the plastic file from under her arm and found the picture of the killer under Jack Hart’s bed. It had been digitally enhanced to show as much of a close-up as possible of the crouching figure. It was chilling. The bottom of her face was visible, but from her nose upwards her face vanished into shadow. The mouth was small and almost identical to that of the young actress.

‘They’ve got the bottom half of the face right,’ said Erika, holding up the picture beside Lottie. ‘I take it you’ll do some close-ups?’

‘The director will do, yes,’ said the young runner.

Lottie took the photo from Moss and looked at it in silence for a moment. There was a crackling sound as rain hit the umbrellas.

‘And it all happened, for real, in that house,’ she said, looking over her shoulder at number 14.

‘Yes. And we’re going to get her with your help today,’ said Moss. ‘Are you sure you’re okay with this? You look far too sweet and kind to be a killer.’

‘I trained at RADA, the Royal Academy of Dramatic Art,’ said Lottie, a little sniffily, handing the photo back to Moss. There was an awkward pause, broken only when the director came over. He was a tall, ebullient-looking man with a red face.

‘Okay, we’re ready to start,’ he said. ‘We’ve got three hours, and then we’ll be moving the unit over to Dulwich to shoot the second murder sequence.’

They went away, leaving Erika and Moss under their umbrella. The sound of the rain increased on the van behind.

‘Does it worry you, that we think a tiny woman like that is our killer?’ asked Moss. ‘You’ve seen what they’ve been writing in the press.’

‘I just find it odd that if we investigate a rape or a murder committed by a man, it’s a given. Men rape women – they murder them, too – and people don’t seem to think they need much of a “reason” to do it… But if a woman does the same, there’s all this soul-searching from society, endless opinions as to the whys and the wherefores…’

Moss nodded. ‘And this one fits the profile for a female serial killer. When women kill, it tends to be far more pre-meditated and well-planned. And poisoning is often a tool of the female multiple murderer.’

‘Although this one couples it with violence, and she stalks her victims at night,’ added Erika.

‘The “Night Stalker”…That was in the Sun today.’

‘I saw it,’ said Erika, turning to look at Moss.

‘It’s good. I wish I’d thought it up,’ grinned Moss.

‘Yeah, well, I’ll remind you of that in the future, when it comes back to haunt us,’ said Erika.

They stared down the street as distant thunder began to rumble and Lottie rehearsed with the cameraman and the director. At the bottom of the road, behind a crash barrier, the banks of photographers snapped away, and members of the public gawked with their camera phones. Coupled with the lookalike actors, and the film crew, it all seemed farcical, reduced to pantomime.

‘Does it worry you we might have it wrong?’ asked Moss.

‘Yes,’ said Erika. ‘But everything worries me. It’s my instinct I have to listen to. My instinct is telling me that this could be our killer. And seeing herself on screen might prompt her to do something stupid and slip up.’

Her phone rang. She pulled it out of her bag and answered.

‘Boss, it’s Crane… You got a moment?’ he asked.

‘What is it?’

‘Do you remember the rent boy who visited Gregory Munro, JordiLevi?’

‘Yeah.’

‘Well, I went ahead and contacted one of our covert Internet investigators, who set up a fake profile on Rentboiz. They’ve been messaging back and forth with him, pretending to be a punter. He wants to meet. Today.’

‘Where?’

‘The Railway pub in Forest Hill, at four o’clock this afternoon.’

‘Great work, Crane. I’ll meet you there at quarter to four,’ said Erika. She came off the phone and relayed the info to Moss.

‘I’ll stay here and supervise our serial killer,’ said Moss, looking over at Lottie, who was now waiting under an umbrella as a lady in a rain poncho applied make-up.