Free Witness the Dead by Craig Robertson Page B

photographer Tony Winter. DI Addison, this is Sam Guthrie, one of our chemists. She’s been taking care of the lipstick for your collar.’
    Winter watched the sideshow, seeing an uncustomary awkwardness in Addison as he realised the joke, and that the innuendo was at his expense.
    ‘Aye, very good. Thanks for seeing us, Miss, er, Ms . . .’
    The chemist smiled and her eyes showed amusement at the DI’s unease.
    ‘Sam. It’s short for Samantha.’
    ‘Sam. Thanks.’
    Fitzpatrick and Winter swapped glances, both enjoying Addison’s discomfort and happy for him to know it. The DI glared at them.
    ‘Right, I’ll leave you to it. I’ve got things to do. Play nice.’ Fitzpatrick hesitated and glanced at Guthrie. ‘Both of you.’
    Guthrie smiled at Addison, her right arm out playfully as if guiding the way. ‘This way, gentlemen, and I’ll bring you up to speed on where we are with your sample. Do you know anything about forensic discrimination of lipsticks?’
    Both men shook their heads, causing the chemist to tut in mock disapproval.
    ‘It’s an interesting science. There was an excellent paper done on it by the Forensic Science Society of Malaysia in 2011. Bit of a field leader. The key is to apply a little TLC. Do you know what TLC is, Detective Inspector Addison?’
    The DI seemed to swallow before answering. ‘Um, tender loving care?’
    ‘Thin-layer chromatography. Lipstick samples that are indistinguishable during visual analysis can be discriminated from each other by a combination of TLC and GC-MS.’
    ‘Okay, I’ll bite. GC–MS?’
    ‘Gas chromatography–mass spectrometry.’
    ‘Right, obviously.’
    ‘We analyse the colouring agents with TLC and the organic components with GC–MS. Okay, see these two lipsticks?’ Guthrie held up two seemingly identically coloured tubes of red within an inch or two of her own lips. ‘What colour would you say they were?’
    Addison shrugged uncomfortably. ‘Like I’d know. Well, they’re kind of blood red. Actually, this is one for you, Tony. Miss . . . um, Sam, you may not know but Tony here has his own patented colour chart for blood. He’s just the man to answer that question.’
    Guthrie looked at Winter curiously. ‘Hmm, I think I may have heard about this. Canteen chat. You differentiate blood by colour according to the degree of oxygenation, right?’
    Nice attempt at deflection, Addy, Winter thought. But, fair enough, he’d play along.
    ‘Yeah, that’s pretty much it. I can make a fair stab at time of death, or at least the time of bleeding, by visual analysis. When it spills from the body, the haemoglobin is fully oxygenated and the blood is bright red like candy apple. Later it loses oxygen and becomes dull and listless like sangria or burgundy. It’s not an exact science but I’ve had plenty of practice.’
    Guthrie turned to look at Addison and raised her eyebrows in bemusement.
    ‘Is he a bit . . . sick in the head?’
    ‘No, he’s just a bit . . . special.’
    ‘Hmm. Interesting. Okay, Tony, so what colour would you say these lipsticks are? According to your . . . chart.’
    ‘I’d say they represent something like three-hour-old blood. Maybe firebrick red or carmine.’
    Guthrie examined Winter for a while as if he were something at the bottom of a Petri dish, before shaking her head at him and turning back to Addison.
    ‘Not exactly what I would call suitably sexy names for a lipstick, are they? I’d suggest something like “passion”, “heat” or “sensual”. What do you think, Detective Inspector?’
    Addison looked from Winter to Guthrie and back again as if he’d stumbled into a madhouse.
    ‘Do they seem the same colour to you, Detective Inspector?’
    Addison nodded resignedly. If it was a game, he was losing.
    ‘They do look very similar,’ Guthrie conceded. ‘But I’ve analysed them with TLC and here’s an overlay of the chromatograms showing the analysis of both lipsticks. One in red and the other in