As expected, the murder suite was empty, and Alice flopped down in front of her computer, beginning to tap its keys before she had even removed her coat or scarf. Typing in ‘Blood donor and alien DNA’ produced a number of possible entries. The first suggested that processed donated blood would be unlikely to yield any of the donor’s DNA, as very few of the donors’ white blood cells would remain in it post-transfusion, and only white blood cells contained nuclei from which the DNA could be extracted. Neither red blood cells nor platelets, the other constituent parts of blood, had nuclei. Any white blood cells remaining in the blood, after processing, would be destroyed either by the standard storage temperature used or, post-transfusion, by the recipient’s immune system.
The next hit initially gave her some hope, suggesting that if the recipient of donated blood left their blood at a crime-scene or wherever, it would contain ‘mixed’ DNA. However, the information was so poorly written and disorganised that any reliance on it seemed foolish. The last but one link led to a paragraph contributed by the National DNA Database of Canada, and it showed a markedly more sophisticated approach. It distinguished between types of fluid transfused, contrasting whole blood, containing red blood cells, platelets and white blood cells, and other fluids which included some but not all of the mix. The author of the article asserted that if the donee received either white blood cells or platelets, or both, then the mixed blood would reveal, on analysis, two separate types of DNA, one attributable to the donor and the other to the donee. It also expressly stated that not only white blood cells, but also platelets, contained DNA. The final piece Alice looked at referred to two studies, one involving a woman who had received fourteen units of blood (four whole blood, ten red blood cells only) and a man transfused with thirteen units (four whole, nine red blood cells only). In both cases, neither individual had detectable levels of the donor DNA profile when tested the day after the transfusions.
As Alice was leaning back on her chair, lost in thought, and still staring at her screen, trying to reconcile the partially contradictory information, Elaine Bell swooped into the murder suite in search of her wandering coffee mug. Spotting it from afar on her sergeant’s desk, she had crossed the room before her colleague had even become aware of her presence. And the gasp Alice released on seeing the DCI betrayed her guilty secret. For a second, she wondered whether her adversary, the cleaner, had planted the mug on her desk from mischievous motives, before recognising the notion for what it was, the product of paranoia and sleeplessness. As Elaine Bell snatched the mug, hissing like a snake about to strike, Alice hurriedly returned to the Google page, hoping that the DCI, still preoccupied with her mug, might not have noticed her unusual research.
‘What on earth are you wasting your time on now, Sergeant? Our time, more accurately, when there are countless things which still need to be done!’ the Chief Inspector thundered.
Still at a loss for words, Alice realised that her optimism had been misplaced. An exhausted, semi-addled Elaine Bell would still be sharper than a cat’s tooth, and that uncanny sixth sense of hers never failed, alerting her to any of her subordinates’ irregular activities.
And it was such a difficult question to answer. Alice had no idea where to start, particularly, as she had not satisfactorily resolved the matter in her own mind. In truth, she was simply dotting ‘i’s and crossing ‘t’s, excluding the improbable, making it the impossible. This had to be done even if it did involve wild speculation or worse. And whatever was left would yield the answer. After all, if Father McPhail was innocent, then they should still be hunting a double murderer, not just on the lookout for some low-life who had assaulted a prostitute. But, losing all confidence in her ability to make her activity sound anything other than madness, even to a well-rested Elaine Bell, never mind the frazzled reality confronting her now, she murmured something about ‘long shots’ and ‘intellectual curiosity’, and waited for the storm to break around her. And it did, its ferocity taking her by surprise until she remembered her own earlier, intemperate reaction to Mrs Donnelly and her concerns. That burden now rested on her lighter than feathers in comparison to the one carried by her tired superior.
‘That Guy Bayley man, have you spoken to him again?’ the Inspector demanded.
‘Not yet, Ma’am.’
‘Well, get a move on, for Christ’s sake!’
After her extended and apparently cathartic outburst, Elaine Bell patted the back of her unbrushed hair, disconcerted to feel a pair of upstanding tufts, exhaled heavily and marched out of the murder suite with a spring in her step, empty-handed. Inspector Manson almost collided with her in the corridor, flattening himself against the wall to let her past. Still striding forwards, she said over her shoulder, ‘Have you checked up McNeice’s alibi, Eric?’ Getting no immediate response, she added, ‘Well, shift your arse then.’
The minute she was alone again, Alice made a quick call to the forensic science lab, praying to herself that someone would be in at such an unearthly hour and that the DCI would not return for the forgotten mug. To her delight the phone was picked up after only four rings, and, better yet, she recognised the voice at the other end.
‘Dave… would you do me a favour?’ Fear of discovery was making her succinct, if not actually terse.
‘Ms Rice, I presume. What can I help you with this time?’ Was there an edge in his voice? One too many favours sought?
She must be clear, get her enquiry across without delay and hope that her near pathological brevity did not cause him terminal offence.
‘Dave, I need to know whether or not it’s possible for X to leave Y’s DNA, as well as his own, if X leaves a sample of his blood at a crime scene or wherever. Assume X received a blood transfusion with Y’s blood at some point before X left the blood.’
It did not sound as lucid as she had hoped it would, but there was no time for rewording the query and he was a bright man. She would have to trust in that.
‘And why do you want to know that, pray?’
‘Because,’ she hesitated momentarily, thinking she heard the tell-tale clump of Elaine Bell’s heavy tread, ‘because if such a thing could happen, it might explain the presence of someone’s DNA at a crime scene – when, if they’re to be believed, they were never there.’
‘OK, Alice. It sounds a bit off the wall, but I’ll check it out for you during my lunch hour. How are you? How are things at St -’
‘Dave. I’m really sorry but I’ve got to go,’ she interrupted him, alert to the sound of the door handle turning, vowing to herself to make it up to him as soon as she could, to explain everything properly. ‘I’ll phone you in the early afternoon. Thanks a million for your help.’
Just as she put the receiver down the DCI re-entered the murder suite and removed the blue and white mug from Alice’s desk, a slightly sheepish smile on her face, hair now brushed flat, ready to face the world.
‘Has your stomach recovered yet?’ Alice asked, the words slipping out before she realised the unintentional barb contained in them. Simon Oakley’s mouth was wide open, about to take another bite out of a cheese pasty. They were waiting in the Astra at Brighton Place for the lights to change, sitting behind a white van that belched exhaust fumes and had ‘I love you’ written on the dirt on its back door.