Looking at the vehicles lined up in the multistorey car park reminded Fry that her Peugeot was due for its MoT this month. She ought to check the date on the certificate – she suspected there were only a few days left before it expired. It didn’t do a police officer’s reputation any good to be caught driving an illegal vehicle.

Sealing off the two top levels of the car park was undoubtedly causing problems. The ‘full’ sign at the entrance had already been illuminated when the first police officers arrived to look at Sandra Birley’s car. Now, frustrated motorists were continually pulling up to the barrier at ground level and reversing away again.

‘What about the lifts?’

‘They’re cleaned out every day,’ said Cooper. ‘The interiors are specifically designed for easy washing and disinfecting. It’s a familiar problem, apparently.’

‘And here I was thinking it was only a problem in high-rise flats on council estates in Birmingham,’ said Fry. ‘You’ve imported some dirty habits into Derbyshire, haven’t you?’

‘Well, I got on to the cleaning contractors a few minutes ago. They swear the lift at the Hardwick Lane entrance was thoroughly cleaned early yesterday morning. So it shouldn’t have smelled of anything but industrial disinfectant with a hint of pine forest when Mrs Birley arrived.’

‘When she arrived, yes. But somebody had been up to their dirty tricks by the time she came back for her car that night.’

‘Do you think she’d have been safer using the lift?’

Fry strode in front of the DCI and gestured at the Skoda, the SOCOs in their scene suits still clustered round it. It wasn’t a murder enquiry, not without a body. So Kessen would disappear soon. He needed to know who had the ideas at an early stage.

‘Well, look at the layout of this level,’ she said. ‘If Sandra Birley used the lift, she’d have had only a few feet to walk before she reached her car. In fact, I think it’s likely she chose that parking space precisely because it was near the lift. But the exit from the stairs is fifty yards further on, and it meant she had to pass the bottom of the down ramp from Level 9 on the way to her car.’

‘Where her attacker may have been waiting behind the concrete barrier.’

‘Exactly.’

‘So it seems her own fastidiousness led her into danger.’

DI Hitchens trotted towards them from the stairs, red in the face and puffing slightly. He was followed by the crime scene manager, Wayne Abbott, who was about the same age as Hitchens but looked much more fit.

Abbott had recently been appointed senior SOCO for the area after finishing a scientific support management course at the training centre near Durham. Fry didn’t much like having to deal with him at a crime scene. There was something about his aggressively shaved head and permanent five o’clock shadow that suggested too much testosterone. From the first time she set eyes on him, she’d wondered why Abbott was a civilian. He ought to be kitted out in full public-order gear, wielding a baton and breaking down doors.