‘She didn’t have many clothes. Even if she rotated them regularly, she’ll have worn this once or twice a week. So maybe this button came off when she was taken? Either in a struggle, or just the process of him getting her into his vehicle? What do you think?’

‘It’s possible.’ As he spoke, Dave was reaching for a box of cotton swabs. ‘And if there was a struggle…’

Paula finished the thought. ‘Then maybe there’s some blood.’

‘Exactly.’ He scanned the shelf above his work station and took down three bottles.

‘What are you going to do?’

‘A Kastle-Meyer test. To see if we’ve got any latent bloodstains. It’s very accurate and you only need a trace for it to work.’ He opened one bottle and dipped the swab in the liquid. ‘Ethanol first. Pure alcohol, Paula. But not for the Methodist Central Hall. We use it to break down the cell walls and release the stain. Makes the test more sensitive.’ He rubbed the swab over the threads on the inside sleeve and then took a second swab and applied it to the material on the outside.

The second bottle had a rubber bulb and dropper built into the cap. Dave added a globule of the contents to each swab. ‘Phenolphthalein reagent,’ he said. ‘And finally, a single drop of what the laydeez use to bleach their moustaches. Hydrogen peroxide.’

‘Don’t be mean, you – holy shit, it’s turned pink. That means blood, doesn’t it?’

Dave nodded, a rueful smile on his face. ‘It does. And how crap does that make me look, that it takes a plod to come into my lab and spot what my highly paid crew has missed?’ Dave tried to sound as if he was taking it lightly, but Paula could tell he was genuinely pissed off.

‘Like you said, Dave, you’d only given it a preliminary once-over. Someone would have picked it up down the line. All I’ve done is speed things up a bit.’

‘Which DCI Fielding will be pleased about. We’ll get on this straight away, Paula. You’ll have a full sample and a database search tomorrow morning.’

‘Thanks, Dave. Oh, and I meant to say, Grisha thinks the killer might have used a taser on her. Could you check for any bloodstains on her clothes on the right shoulder, the left thigh and the stomach in the navel area?’

He rolled his eyes. ‘Now she tells me. I’ll get somebody on it and see what we can come up with. Go on, get out of here before you end up busting the budget.’

Paula grinned. ‘It’ll be worth it when we catch the bastard.’

‘Save it for Fielding,’ Dave said. ‘Times like these, I bet you miss Carol Jordan.’

Paula’s good humour vanished, banished by his words. ‘Every day. Every bloody day.’