‘That single photo frame is really bugging me,’ she said as she pulled on to the main road towards Saltern. ‘D’you reckon CID might want to take a look at this?’

Jay pulled a face. ‘Not really their thing, is it, Stace? Peeping Toms aren’t high profile enough for the detectives, are they?’

Stacey laughed. ‘I’ll forgive you this time, Jay, but you’ll soon learn that the Saltern-le-Fen detectives aren’t like the ones back where you came from.’

‘What? Not a bunch of toffee-nosed gits who think they’re better than us plods? You’re having me on.’

Stacey laughed even louder. ‘If you’re good, PC Acharya, tomorrow I’ll introduce you to DI Jackman and DS Marie Evans. Then I’ll watch you swallow your words.’

Jay made a face. ‘Thanks a bunch. Really looking forward to that.’

‘I think you’ll be pleasantly surprised, sunshine. Now, back to our Ratty. He’s been up to his tricks for years. Why? Because he can. He gets this weird kind of pleasure out of just being inside someone’s house without them knowing he’s there. The psychologist said it’s a sort of game, a control thing, just to prove he can do it. He’s never touched anyone or taken anything, and he’s not a voyeur. Plus he’s never actually broken in, never damaged a lock or forced a window. He looks for weak points and takes advantage of people’s carelessness. Up until a few years back, even if we had caught him inside, it was a civil matter.’

‘You saw him in action once, didn’t you?’ said Jay.

Stacey laughed again. ‘Did I just! Ratty is about six stone wringing wet, skinny as a rake. He’s in his fifties but he can scale a wall in seconds. I heard climbing’s been classed as an Olympic sport — well, Ratty could be our hope for gold.’ Out on the main road, she changed gears. ‘I was only a few minutes away when I got a call to say someone had seen this sneaky-looking little guy hanging around a house in Cedar Grove. It was an oldish property with this climber up the wall, and he’d just started up there when I arrived. He went up the side of that house like a spider. He saw me, swung into a tree near the house, jumped down and was gone in seconds.’

‘Impressive!’ Jay grinned.

‘You can say that again.’ She became serious. ‘But why did he suddenly want to take something? It bothers me, that does.’ She shook her head. ‘I really hate it when someone acts out of character!’

‘Deep breaths, Stace!’ said Jay, grinning. ‘Think of your blood pressure!’

‘PC Acharya, you’re lucky I’m driving, otherwise you’d be going home with a thick ear. Now, come on, tell me why someone who’s been following the same pattern for years suddenly does something so out of the ordinary.’

They drove on in silence. Neither had an answer. For her part, Stacey was well aware that most people would consider the appropriation of a family photo to be a minor problem, low on the list of issues the police had to deal with. But things that made no sense bothered her. Ratty was no thief, and he wasn’t a voyeur. As far as they knew, getting inside other people’s property gave him no sexual gratification whatsoever. He simply relished the challenge of gaining access and seeing how close he could get to the occupant without being seen. So, why on earth steal a simple photograph and finally risk arrest?