But that didn’t explain why White thought he needed a distraction in the first place. Nor did it indicate his wider involvement in the recent deaths.

It still wasn’t clear whether they were after one person or several. Hawkins’ own theory, about a killer bent on finding supposedly possessed individuals and cleansing them of their uninvited guests, might still be correct. But it was also plausible they had stumbled across infighting between different factions of the spiritual community, one of whom was using these fears to draw the opposition to their deaths.

Either way, the fact that Joseph White clearly wanted to avoid attention from the law meant he must have had some kind of stake in the situation.

Initially, his strategy had worked – buying him a few days’ reprieve. But he clearly hadn’t banked on Mardell being located so fast, nor revealing his identity once cornered. Plus, his overall strategy seemed flawed.

His choice to use Mardell as a distraction during Hawkins’ visit could be explained by the short notice she’d given him between calling ahead and turning up at his door. But the tactic itself – to create a diversion that could be traced back to him if it went wrong – seemed ill-judged.

Something didn’t add up.

They had arrived in Cavendish Square to find White’s office lights on. But the door was answered by the cleaning lady, who said her employer had left a few hours early that afternoon – shortly after Hawkins’ latest visit – although he hadn’t said where he was going. His assistant, Tom, had left a couple of hours later, at five.

With gentle persuasion, the cleaner had been convinced to let the two detectives in, but after a quick search of the founder’s office, they had uncovered no clues to his current whereabouts.

Hawkins’ next target, of course, was White’s home.

Unfortunately, if he was inside, the founder wasn’t keen on talking to them, while motorized security gates prevented them from accessing the rear of the block, presumably where windows might give further clues to whether or not the flat was occupied. Even if the place was empty, however, until her team came up with somewhere else for them to try, she and Maguire might as well wait, in case White returned.

They exited the lobby and walked through the manicured garden area towards the Giulietta, which was out on the street, an inconspicuous distance from the property. As they reached the pavement, a BMW 4x4 pulled off the road and stopped outside the powered gate leading under the flats to a private car park beyond.

Hawkins changed direction, moving towards the vehicle, as the motorized shutters began to open.

‘That ain’t our guy,’ Mike called from behind her. ‘White drives a Jag.’

‘I know,’ she said. ‘But he’s ground floor, isn’t he?’