"We know that the killer is using anticoagulants and we know that Neil Munro had a whole cupboard full of them hidden away in his lab."
"Neil couldn't have been the killer."
"I know that but it's an uncomfortable coincidence don't you think?"
Fenton didn't get a chance to reply for they were joined by Charles Tyson and Nigel Saxon who asked them if they were having a good time. He held up a bottle of whisky in front of them. Fenton declined but Ferguson offered his glass to have it topped up.
"Dr Tyson tells me you are on duty on Sunday morning Ian is that right?" asked Saxon.
"All too true I'm afraid. Why do you ask?"
"I have to dismantle the Saxon analyser some time in the afternoon. I wondered if you might be willing to stay on to give me a hand?"
Ferguson made an apologetic gesture. "If only you'd said sooner," he said. "But I've arranged to meet my girlfriend in the afternoon. Maybe I could put her off if I…"
"I'll do it," interrupted Fenton.
"You're sure?" asked Saxon.
"Of course. I've been idle for so long it'll be a pleasure."
"Well, if you're quite certain…"
Fenton arranged to be at the lab by two o'clock on Sunday afternoon.
On the way home Jenny asked Fenton, "What did Alex Ross mean by the 'Tree Mob'?"
"I've no idea," replied Fenton.
"Charles Tyson knew," said Jenny. "I read it in his face."
Nigel Saxon was waiting outside the lab when Fenton arrived on Sunday afternoon. He was stamping his feet and throwing his arms across his chest to keep warm as he patrolled the kerb near his parked car.
"Not late am I?" asked Fenton, checking his watch to find out it had just gone two.
"Not at all," smiled Saxon. "I'm grateful to you for helping out. The company is a bit short of demo models and this one has to be shown at Glasgow Royal tomorrow. You can have it back afterwards for a few more days."
The two men set about dismantling the Saxon Analyser with Saxon concentrating on the hardware and Fenton disassembling the supply lines and removing the reagent reservoirs. Fenton came to a blue plastic container among the tubing and asked Saxon what it was.
"Be careful with that," warned Saxon. "It's the acid sump."
"I'll get rid of it down the drain in the fume cupboard," said Fenton disconnecting the blue cylinder from its manifold and removing it carefully.
Saxon said, "I'm just going to nip out to the car for a moment to get my socket set."
The door banged behind Saxon and Fenton carried the blue container slowly across the lab to the fume cupboard to place it inside the chamber. He turned on the fan motor and heard the extractor whine into life. The fan would suck any toxic fumes up through a flu and vent them to the outside through an aluminium stack on the roof of the building.
Fenton had unscrewed the cap of the acid bottle and was about to start pouring the contents down the drain when suddenly he froze. There was a bottle of benzene sitting inside the cupboard and he realised that he could smell it! He could smell benzene!
How could that be? he asked himself. The bottle was on the other side of the glass screen and the fan was running. How could the fumes escape? He put the cap back on the acid container and took a few steps backward. Everything looked and sounded normal but there was something very wrong. He lit a piece of scrap paper in a Bunsen burner and held it to the mouth of the fume cupboard. The flame did not flicker. The extractor fan was running but there was absolutely no air movement through the flu. As a safety device it was totally useless.
Puzzled as to what the fault could be Fenton brought some step ladders across to the fume cupboard and climbed up to inspect the motor housing. It seemed in good condition. He then moved on to the filter block in the chimney stack and found the source of the problem. The fire damper had closed. Fire dampers were fitted as a safety measure to fume cupboards. In the event of a fire in the lab they isolated the chamber and prevented flames from reaching highly volatile chemicals via the flu. In this case the damper had apparently closed of its own accord and rendered the fan ineffectual.
The satisfaction that Fenton felt at discovering the cause of the problem was immediately replaced by distinct unease when he saw why the damper had closed. The retaining clips were missing. He searched the area at the base of the filter block but failed to find them. There was a chance that they had snapped and fallen down inside the flu but there was also a possibility that they had been removed deliberately.
Fenton came down the ladders and rested his foot on the bottom rung for a moment while his mind raced to find a motive for sabotaging the fume cupboard. After all nothing drastic would have happened if he had gone ahead and poured the acid down the drain — an unpleasant whiff of acid fumes perhaps but nothing too serious unless…
Fenton's gaze fell on the drain he been about to pour the acid down and a dark thought crossed his mind like a cloud across the moon. Wondering if paranoia were getting the better of him. He squatted down and examined the pipe leading down from the drain. He was looking for signs of recent dismantling. He failed to find any but remained uneasy. He had to know for sure. He fetched a spanner from the lab tool box and undid the coupling at the head of the bend. Gently he slid out the curved section of pipe and looked inside. His fingers were shaking slightly as he saw signs of a chemical lying in the trap. Cautiously he sniffed the end of the pipe and recognised the smell. It was potassium cyanide!
If he had poured acid down the drain on top of cyanide crystals when the extractor was non-functional the whole lab would have been filled with hydrocyanic gas within seconds and everyone in it would have died.
Everyone in it? thought Fenton. He was the only one in it and where was Saxon? He had been gone for ages.
Nigel Saxon came in to the lab carrying a tool box. "Couldn't find the damn thing. It was under the back seat."
"Really?" said Fenton looking Saxon straight in the eye.
"Good God. What's happened?" asked Saxon as he caught sight of Fenton's face. "You look as if you've seen a ghost."
"There's something wrong with the fume cupboard," said Fenton.
"Is that all?" asked a puzzled Saxon.
"There are cyanide crystals in the drain."
"You mean the drain is blocked?"
Fenton stared at Saxon for a full thirty seconds before saying, "If I had poured acid down it…"
Saxon shook his head and said apologetically, "I'm sorry. I'm not a chemist. What are you trying to say?"
Fenton was desperately trying to appraise Saxon's behaviour. He seemed genuine enough. But did he really not know what the consequences would have been? Had it really been coincidence that Saxon had chosen that particular moment to be out of the room?
Fenton's head was reeling. Had someone really tried to kill him? He searched desperately for another explanation but all he found was a new suspicion. He faced the possibility that the incident in the pub had been no accident either, no act of mindless violence as the police had called it. It appeared that someone wanted him out of the way and whether it was temporary or more permanent did not much seem to matter. But why? Whoever it was must think that he knew more than he did. How ironic if he were to end up being killed for something he never knew in the first place.
The flat was empty when Fenton got in for Jenny had gone to visit some of her old flat mates. But Fenton was glad of the time it gave him to calm down. His hands still shook a little and his insides still felt hollow but a stiff whisky helped fight the symptoms and prepared him to confide in Jenny when she did come in.
"But why?" exclaimed Jenny when Fenton told her.
"I keep telling you I don't know," maintained Fenton.