He produced the small leather wallet from his pocket and unfolded it to reveal a set of lock picks. Selecting a torsion bar and medium pick, it took him less than one minute before the door swung open, revealing a dark interior within. He took a torch from his pocket and swung it into the property. Sure enough, the apartment was completely unfurnished: just blank walls and an untouched kitchen. There were deep carpets everywhere but not a stick of furniture.

Switching off the torch, he walked to the balcony, slid the door open, and took out some binoculars from his jacket pocket. Putting them to his eyes, he located the Brankos’ flat by its floral curtains.

‘Perfect,’ he said. ‘Wait here. I’ll go and get the kit. I’ll knock three times.’

He disappeared from the apartment, leaving Pet alone in the gloom. She sat on the floor, taking out her laptop and a small metal box and connecting them together with a small cable.

Tom returned within five minutes, carrying the holdall, which he began to unpack as soon as he was inside. Leaving the sliding door to the balcony partially open, he erected the two tripods and then, using his binoculars, aimed the laser at the far corner of the Brankos’ window.

‘Same again, Pet: tell me when you see the laser behind you.’

He made fine adjustments with the tripod until a single, small, red pinprick of light appeared on the kitchen unit behind them.

‘Now,’ said Pet.

Tom moved the photodiode and tripod into the laser beam and screwed the platform securely into place once the beam hit the component’s centre.

‘Okay, you have the laptop ready?’ he asked.

‘Come on now, Detective, you don’t think I’m just sitting here in the dark, do you? This is my bit.’

Pet connected the small metal box into the leading cable from the photodiode and extended two stubby antennae.

‘I’ve used this to hook into the building’s Wi-Fi. I’ve bounced the signal to come direct into my computer without the need for us to sit here or trail wires up. We may as well get comfortable.’ She busied herself on the Mac for a minute longer before saying, ‘I’m done. We’re good to go.’

Tom nodded and they left the apartment, closing the door behind them.

Back in apartment 618, Pet sat on the corner sofa, snapped open her laptop, and tapped at the keyboard. Lines began to dance slightly across the screen, but no discernible sounds emitted other than a hiss of static.

Tom went to the window with his binoculars and focused in on the Brankos’ window, which was in total darkness.

‘No one’s at home just yet,’ he said, looking at his watch, which showed it was just after 7pm.

‘So what do we do now, Detective?’

‘We wait, I guess.’