Fry found she had no idea. She couldn’t even guess. In fact, she knew nothing else about Slovakia, except that it was where the photocopier paper was made that they used in the office. It said so on the packaging.

She hated being so ignorant of important facts. And this could be an important one, since it made a difference to the nationality of the victim. Damn. It was an overlooked detail, and she didn’t like them. The wrong loose end could unravel a case completely.

She took her notebook out of her bag and jotted down a reminder to herself. She supposed she could call someone back in Edendale on her mobile, but she didn’t want to seem like a pest, some sad character who couldn’t leave her desk behind. Everyone else in the office seemed to be convinced that she was the lucky one to be flying to Ireland. A day off, they called it. A jaunt, a little jolly. She’d been conscious of envious glances, as if she was the teacher’s pet. ‘Don’t drink too much Guinness, Diane. And watch out for those leprechauns.’

Fry became aware that she was getting a headache. And she hadn’t brought her Lemsip capsules with her, so it was guaranteed that an hour in the recycled air of an economy class cabin would make her cold twice as bad. It had been lurking around for days now, barely suppressed by the medication, irritating her nose and throat. If she didn’t do something, she would arrive in Dublin with a sore throat, barely able to speak.

Well, she still had twenty minutes to spare before boarding, and there were some shops airside. No Boots the Chemist at a small regional airport like Robin Hood, but at least there was a World News. All the essentials for the happy traveller.

Keeping an ear out for announcements, Fry browsed the small range of pharmaceutical products on offer. She picked up a packet of Lemsip and some Paracetamol, then noticed the Sudafed. She wasn’t congested, not yet. But that was the worst symptom of a bad cold, and you couldn’t be too careful.

Out of habit, she turned each packet over to read the ingredients and contra-indications. She wasn’t a hypochondriac, but if she ever had an allergic reaction, she wanted to know exactly what she was allergic to.

Her eyes were drawn to the active ingredient in Sudafed. Pseudoephedrine. That word had been bothering her since she’d gone over the chemist’s report earlier in the day. There had been traces of the chemical found at Pity Wood Farm, scattered through the outbuildings and even in the soil surrounding them.

What else had there been on the list? Hydrogen peroxide, dilute hydrochloric acid, drain cleaner, iodine, anti-freeze, rubbing alcohol. And pseudoephedrine. A lot of pseudoephedrine. There was something she was missing, a loose end nagging at her here.