Page 53 of The Scene of the Crime

Jessica nodded. ‘But he could have gone to any garage in the area. All the local garages should be checked, but the one by the roundabout is at the top of the list. We know the timeline from the break-in to the car being found, so that’s a big help. There’ll be a till record and maybe credit card details if he bought a petrol can and filled it up.’

‘He could have an accomplice who got the petrol or set the car alight,’ Guy added.

Diane picked up on his thoughts. ‘The intruder could have gone to the De Klerks’ house with an accomplice.’

Jessica disagreed. ‘If that were the case, it’s odd the accomplice didn’t enter the house or wait outside in a vehicle before leaving the scene together.’

Guy had a thought. ‘If there were other people involved, they would need to make contact, either in person or by phone. If whoever stole the car used a mobile phone after leaving the scene, the cell masts would pick up the phone signal along the route.’

‘But we don’t know his mobile number,’ Diane pointed out.

‘We don’t need to. We can ask the four leading network providers for details of all the mobile phone numbers pickedup by the masts from Hackney Wick and along the A12 to the roundabout. I can then look for numbers that move quickly from cell to cell, indicating the caller was travelling in a car. If I find a number linked to cell sites along the route, we can ask the service provider for the owner’s details, and any calls and texts they made . . . and its current cell site location.’

Diane looked confused. ‘But surely there will be hundreds, if not thousands, of phone numbers to look at?’

‘You’re right, but using a computer program to search for and identify a recurring number makes the task much easier.’

‘What if they made an internet call on WhatsApp or FaceTime?’ Jessica asked.

‘It’s a bit more complicated, as WhatsApp uses end-to-end encryption, but it uses the same connection to your phone’s network to send messages and make calls, even though it’s over the internet. A microchip modulates a radio wave that travels to a nearby cell tower which . . .’

‘We’ll take your word for it,’ Jessica grinned.

‘Wow, I’m so glad you’re on the team,’ Diane said. ‘We know very little about phones and computer forensics and all the jargon that goes with it.’

‘All I need is a detective inspector’s authority for the service providers to give us the information,’ Guy told Jessica.

‘I’ll ring DI Chapman from my office,’ Jessica said, unzipping her protective crime scene suit.

‘You can call him if you want,’ she added, looking at Diane.

Diane blushed. ‘No, it’s fine, thanks. I’ll leave it to you.’

Jessica phoned Chapman and told him about the possibility the intruder lived locally and used the Jet garage to buy the petrol used to torch the Range Rover. She also told him about Guy’s idea of cell site analysis to try and identify and locate a phone that the intruder might have used.

‘Great,’ he answered. ‘I’ll get some of my team onto the garages, and I’ll email you the authorisation to get the information from the mobile service providers.’

As promised, Chapman quickly emailed Jessica a signed authorisation form shortly after their call ended. She’d just put it on Guy’s desk when he and Diane walked in looking pleased.

‘Look what we found among the debris.’ Diane held up a clear plastic exhibit bag containing something small and metallic looking.

‘A cigarette lighter?’

Diane nodded, handing it to her. ‘It’s badly burnt and a bit melted, but there’s some sort of design on it and what looks like writing, which could be someone’s name. I’ll ask Taff if he can clean it up so we can see the engraving better.’

‘Clean up what?’ Taff asked as he entered the room holding a folder.

Jessica handed him the exhibit bag.

‘Ah, a lighter,’ he remarked.

Diane turned to Guy. ‘As you can see, Taff’s powers of observation are comparable to that of the great detective . . .’

‘Sherlock Holmes,’ he interrupted.

‘Actually, I was going to say Inspector Clouseau,’ she said with a grin.

‘Can you clean this up enough to see what’s engraved on it?’ Jessica asked.