She looked around, trying to visualise the scene two hours earlier as Fletcher sprinted down this path. What was his plan? Or maybe he had no plan. Maybe this was a spontaneous act of barbaric cruelty fuelled by God knows what petty grievances.

Her phone rang. It was DI Eva Bose from the office, who had been updating her all morning. As ever, she had proved capable and succinct, passing on what was vital, and shielding Gabriel from the irrelevant. Nothing was more irritating for Gabriel at the initial stages of an investigation than being deluged with trivia.

‘Eva. We’ve just arrived. There’s a CCTV camera at the staff entrance,’ said Gabriel. ‘Have Kent Police got the video yet?’

‘Yes, ma’am,’ said Bose. ‘Fletcher came past the security barrier three minutes after the attack ended. He grabbed his bike from the rack and cycled north. The closest council CCTV is half a mile down the road. We’ve got a team pulling it from the local authority.’

‘What about his phone? Anything from GPS or cell data?’

‘Sadly not, ma’am,’ said Bose. ‘We’ve got his number, but the phone’s been switched off since the attack. We’re pulling historic phone records, of course, and ploughing through his regular contacts.’

Bugger, thought Gabriel. Phones had transformed investigations more than anything else since she had joined the force twenty years ago. The GPS running constantly in the background of smartphones meant it was possible to locate the owner to within a few hundred feet, either in real time or at any time during the last few weeks or months as long as the phone was on.

Bose continued: ‘We’ve also got his bank details and an alert’s in place, so we’ll know the moment he uses a card or withdraws cash. We’re pulling social media contacts as you’ve requested and fishing out any interesting sites he might have used.’

‘Latest casualties?’ Gabriel asked.

‘Six now confirmed dead at the scene, one dead in the ambulance, three more serious at Thameside Hospital. The comms team have been deluged with media requests and there’s a horde gathered outside the Yard following on from the three-line statement Kent Police put out earlier, so we’ve put out a holding statement. It says… hang on…’ she rustled for a piece of paper, ‘…it says, “Terrorism is one motive being considered and the Met’s counter terrorism detectives are working closely with colleagues from Kent on the initial investigation.” That’s it.’

‘If that doesn’t bore the pants off them, nothing will,’ said Gabriel. She ended the call. She could see the trajectory of the coming media storm clearly in her head – with all its speculation, blame games and half-truths – and the thought of being thrust back in the spotlight again left her cold. But that was for later.

#

The scene-of-crime officers were at work in their white paper over-suits, inching like beetles over the ride’s platform as a local uniformed constable waved Gabriel and Campbell through. Gabriel unzipped her go-bag – the pre-packed holdall that contained everything she might need at a crime scene – and yanked out a paper suit and rubber gloves.