"Speaking of bad taste," I said, changing the subject, "Do you think it could have been Charlie Bales who put that suit in your office?"

Zara looked at me, eyebrows raised in sudden realization. "Yes! It could have been, couldn't it? Charlie's got a really weird sense of humour. He's forever playing jokes on people. One time he made me sniff one of those bottles of stuff he keeps for the polar bears. I nearly pa.s.sed out."

"He did that to us, too," I said.

"Did he? That's the kind of thing he finds funny. It's sick, really. Yes, I bet it was him." There was a pause and then she said, "I've got to feed the c.o.c.kroaches and things. Then I might as well be off home, I suppose. I was meant to be doing a session for the St Mary's Sunday School outing but everything's been cancelled. Oh, well. At least I don't have to face any more kids today." She smiled weakly and went on her way, leaving me and Graham with plenty to talk about. We meandered towards the proboscis monkeys' enclosure, finally coming to rest on a bench that was half hidden by a clump of bamboo. Kylie was in the kitchen, chopping fruit again. We tucked ourselves into the vegetation so that she wouldn't be able to see us but we would still be able to hear if anything interesting happened.

"Charlie Bales," I said softly. "I think we ought to keep an eye on him."

"He couldn't have done it," said Graham firmly. "He was vomiting the entire time. It would have been physically impossible."

"OK, but I reckon he definitely did the thing with the tiger suit. He could have done the graffiti, too, couldn't he? He was the one who called Mr Monkton on his walkie-talkie. He wanted to make sure his boss saw it."

"He might well have wanted to unsettle his employer," Graham conceded. "But it doesn't necessarily follow that he planned his murder."

"Maybe not. But he was really angry about having to do those logs for the polar bears and then not having time to go home and get changed before the party."

There was something else about that whole business a something that was tickling away at the back of my mind. I frowned in concentration. "Graham," I said at last, "you know when April came down to tell Charlie to sort out the bears?"

"Yes..."

"Didn't he say he'd fed them already?"

"Yes, I believe he did. In fact, as I recall, his exact words were: 'They were fed this afternoon.'"

"Then he was lying!" I said triumphantly. "I mean, we were with him, weren't we? He didn't give them anything. In fact, he told us he'd fed them in the morning. But suppose he hadn't...?"

"What are you suggesting?" asked Graham.

"What would have happened if the bears had been really hungry?" I demanded.

"Two ravenous carnivores?" Graham replied thoughtfully. "I'd have said it offered an extraordinarily efficient way of disposing of a body."

"So if April hadn't come down... If Charlie hadn't fed them... Mr Monkton might never have been found! Those bears wouldn't have left a shred of evidence."

We stared at each other, aghast, and for a few seconds we were completely silent. Which was just as well, because at precisely that moment Charlie Bales himself decided to pop in for tea and biscuits with Kylie.

"There is justice in the world after all," he told her, not bothering to lower his voice as he pushed open the door to the kitchen. "Put the kettle on, love, and crack open the chocolate biscuits. Let's celebrate. Our glorious leader has finally got what he deserved."

"Shh!" Kylie hissed urgently. "What if someone hears you? You shouldn't say stuff like that!"

"Come on, Kylie, you didn't like him any more than I did. Think of what he did to Sandy! Archie, too, for that matter. He got what was coming to him."

"Maybe," Kylie conceded. "But you shouldn't say it. Not now. Keep your mouth shut. The police..."

Charlie interrupted her with a scornful grunt. "The police are useless around here. They couldn't even track down a stolen bike, I reckon. Trust me, Kylie, they'll never work it out."

"They were here in the kitchen this morning, asking about that old tiger suit."

Charlie stiffened. "Did you tell them anything?"

"Of course not. But someone will. You should never have taken it out of that bin."

"Maybe. Maybe not." Charlie sniffed dismissively. "It was just a joke. It doesn't mean anything."

Kylie chopped away in silence for a few moments. Then she said, "That policeman said he was stabbed. Lots of times." Her voice rose higher.

Beside me, Graham gave a sharp intake of breath. My mouth fell open.

"That's what they told me, too," said Charlie casually.

"Inspector Murray said that some of the wounds were really deep. But others just glanced off his ribs." Kylie looked up at him miserably. "Who killed him, Charlie?"

Charlie laughed. "We'll probably never find out who struck the fatal blow. Pity, really. I'd like to shake the killer by the hand." His words sent a shiver down my spine. Draining the dregs from his mug, Charlie kissed Kylie goodbye and walked away.

Between the bamboo leaves, Graham and I watched him swagger jauntily down the path.

For someone who had spent the previous evening heaving his guts up, he looked surprisingly perky.

the african savannah.

Graham checked his watch. It was almost time to meet Mike Hobson. Once Charlie was out of sight we freed ourselves from the bamboo and headed through the Frozone towards the African Savannah. According to our schedule we'd be meeting the giraffes, mucking out the zebras and feeding the baby elephants.

"What did Kylie say yesterday?" I asked Graham nervously. "Isn't the elephant the most dangerous zoo animal of them all?"

"That's what she said," he replied, his voice wobbling just a little. "But surely their calves shouldn't prove too much of a threat?"

We stopped and looked at each other uncertainly.

"I suppose there's only one way to find out." I shrugged, then changed the subject. "Charlie seems to have recovered from his illness very quickly, doesn't he?" I said.

"Yes, he does. But I believe that would be consistent with mild food poisoning."

"Mmm... I'm not so sure. I reckon he might have been faking."

Graham frowned, puzzled. "I can't see how he'd have managed it. We both heard him, didn't we?"

We'd reached the penguin pool by now, and at precisely that moment Charlie came marching breezily up the path, whistling and swinging a bucket of sardines in each hand. He acknowledged us with a brisk nod as he let himself into the enclosure. An eager rockhopper waddled towards him and he threw it a small fish. There was no escaping it: Charlie looked healthy. Robustly healthy. Suspiciously healthy.

An idea began to take shape as we walked on. As soon as we were out of earshot I said urgently, "No one went to check on him last night, did they? And we didn't actually see him. We just heard him being sick, that was all."

"What do you mean?"

"Pop singers mime along to their songs sometimes, don't they?"

"True." Graham nodded solemnly. Last Christmas we'd been tricked by someone doing just that.

"Could Charlie have been using a recording?" I asked. "He might have gone into the toilet, switched on the player, rung Mr Monkton on his mobile to get him to go to the bear pit, then climbed out of the window. He could easily have stabbed Mr Monkton, then got back in without anyone knowing."

"It's technically possible for him to have broadcast the sound of vomiting," said Graham slowly. "There are all kinds of ways he could have done that. But there was the smell, too. It was vile when I visited the gents'. It's a very distinctive aroma."

"Yeah." I deflated instantly. "I don't see how you could fake that." We trudged on through the Frozone, past the little kitchen where Charlie had almost made me keel over the day before. In my head a great big light bulb suddenly lit up. "Those bottles!" Stopping dead, I stabbed a finger at Graham's chest. "Putrescine! Cadaverine! Suppose Charlie's got one in there that smells like puke?"

"What a dreadful thought!" Graham exclaimed.

"He could have, though, couldn't he?"

"Theoretically, yes. I suppose you could manufacture that kind of odour."

We both looked at the closed kitchen door.

"You're not suggesting we find out?" asked Graham weakly.

My legs felt wobbly at the very thought. I mean, I'd nearly pa.s.sed out the day before. I wasn't exactly keen to repeat the experience. I took a deep breath. "Look, Graham," I said, summoning up my courage. "Charlie definitely did that thing with the tiger suit a he more or less admitted it back there. We know he hated Mr Monkton. He's got to be the killer. But if we're going to tell the police, we need proof. We've got to know if one of those bottles contains the scent of sick. We're going to have to sniff them."

Graham gulped and looked green about the edges and I felt exactly the same. We'd be late to meet Mike Hobson, but it felt like we had no choice.

Graham checked his watch. "It will take Charlie about ten more minutes to feed the penguins. We'd better be quick."

Seizing our opportunity, I turned the handle and opened the door, and together we sneaked into Charlie's kitchen.

A whole row of bottles lurked nastily on the top shelf. I took down the first and, holding it at arm's length, gingerly lifted the stopper a fraction. The ghastly aroma of long-dead fish wafted out. Hastily pushing the stopper back in, I replaced it on the shelf.

"OK," Graham croaked courageously, "I suppose it's my turn."

He took down the second bottle and raised the stopper no more than a millimetre. Weirdly, the smell of strong coffee filled the room.

"Lucky you," I grumbled, removing the gla.s.s stopper from the third. It was full of cheap aftershave. The next one stank of poo. Then it was wee. We worked our way along the entire shelf, feeling steadily more ill with each disgusting aroma. When Graham pulled the stopper from the very last bottle, the unmistakable scent of sick filled the room. Queasily triumphant, I looked at Graham. "Bingo! This is all the proof we need. We'd better find Inspector Murray."

Graham opened his mouth to reply. But before he'd managed to get a single word out, a gunshot rang across the grounds. Monkeys screamed in alarm. Tigers roared. Gulls took to the skies, shrieking.

And Charlie Bales fell face down into the penguin pool, stone dead.

teamwork.

S.M. WILL BE AVENGED!.

It was scrawled on the path beside the pool where Charlie Bales lay as dead as the fish he'd been throwing to the penguins. I dimly registered something odd about the choice of words, but in my shocked state I couldn't figure out what it was.

Inspector Murray arrived on the scene about two seconds after us. He took one look at the dead keeper and then ordered Graham and me to wait for him in the hotel. We sat in a dark corner of the lobby, muttering quietly to each other.

"Charlie's death has got to be connected with Mr Monkton's, hasn't it?" I said.

"Undoubtedly," agreed Graham.

"OK... Mr Monkton. Let's start with him. Inspector Murray didn't tell us about those stab wounds," I said resentfully.

"Perhaps he thought it was an unsuitable subject to discuss with minors," replied Graham.

"It sounds weird, though," I puzzled. "Some were really deep. You'd need to be pretty wound up to do that, wouldn't you? But others just glanced off his ribs. How could that happen? You'd have to have your eyes shut. Or not be trying hard enough." Another possibility suddenly hit me like a sledgehammer.

Different wounds.

Different blows.

Different hands holding the knife.

"Graham," I whispered, my eyes practically popping out of my head. "Suppose they all did it?"

"Who? What do you mean?"

"Well, we agreed that everyone had a motive even if they didn't have the opportunity, didn't we?" I said. "I reckon this is about justice. It's Payback Time for Sandy's death. And Archie's. Just like Charlie said. Mr Monkton was cleared of blame at the inquiry, so they all decided to kill him. Maybe everyone who left the room that night was involved: Charlie, Kylie, Pete, Mike, Angie, Ron. Jerry, too. That's why their alibis backed each other up a they'd planned it beforehand. One blow each. No one would know who struck the fatal wound. That's why Kylie asked who killed him and Charlie said, 'We'll probably never find out.' And if the original plan had worked, the bears would have eaten Mr Monkton and the police wouldn't have known he'd even been stabbed. It would have looked like an accident a like he'd fallen in or something."

"It sounds perfectly plausible," said Graham. "But where does Charlie's murder fit into this highly orchestrated scheme? Who killed him?"

I thought about Charlie. Loud. Breezy. Over-confident. "Mike said something about Pete being compet.i.tion for Charlie, didn't he? Do you think Pete's in love with Kylie?"

"In the USA, love triangles are number seven on the list of most common reasons for murder," Graham informed me.

"Plus, Charlie couldn't keep quiet. Kylie told him to shut up but he wouldn't. He was really full of himself. He was putting everyone in danger."

"But why write those words on the path?"

"It must have been a diversion. As soon as Inspector Murray gets here, we'll tell him."

Mum had to be pulled out of a Seaweed Wrap treatment to attend our interview. She wasn't very happy about having to sit there plastered in green gunk wearing nothing but a dressing gown. We kept everything brief and to the point, but if the policeman was impressed by our theory, he didn't show it. He listened carefully and nodded thoughtfully before telling us, "I hate to disappoint you, but the keepers' alibis are absolutely watertight. Of course we'll check and double-check, that's routine police procedure. But I'm sure that none of them was involved."

When he'd finished with us, Mum disappeared back into the spa and the policeman went in search of keepers to interview. We were allowed to spend the rest of the day doing what we were scheduled to do with Mike Hobson, but he wasn't exactly welcoming. In virtual silence we fed the baby elephants a who turned out to be perfectly harmless and very cute. Then we visited the giraffes, who seemed to lower their heads out of the sky to take their bananas. Mucking out the zebras was hard work, so we didn't really have time to think or talk.

We finished at 4.30 p.m. again and went back to the hotel for another scented bath. The Ballroom Cafe was shut, seeing as the zoo hadn't been open to the public all day, so we had to chew our way though a couscous, halloumi and spinach salad in the hotel restaurant with Mum and Becca. It wasn't exactly filling. Then Mum insisted we sit down together in her room to watch a jolly musical on TV that she promised would "take our mind off things". It didn't work. We were all tense and preoccupied, and when we eventually crashed out, I couldn't get off to sleep.

I dozed fitfully and tossed and turned for ages. When I finally dropped off, I had a horrible dream about being on a rollercoaster that was out of control. I was hurtling into oblivion when I suddenly snapped wide awake.

And then I knew what was odd about the writing on the path.

S.M. WILL BE AVENGED!.