Day 13, 16:50

Pinkie wasn’t the least bit surprised to find Octavia and Rarity standing as far away from one another as possible when she entered the entrance hall, the latter still looking deeply regretful while Octavia just stood looking sullenly in the opposite direction. As Pinkie trotted down the staircase, Maud and Fluttershy entered from the side door. Seeing that they had all arrived, Octavia led the way out to the courtyard without a word.

“Are you all ready?” Pinkie asked the remaining three.

Fluttershy nodded weakly, Rarity muttered something in response that Pinkie couldn’t make out, and Maud just remained silent.

“Alright then,” Pinkie continued, a little agitated.

Following Octavia through the gates, with the others a few feet behind, Pinkie entered the courtyard. As she took her position in the far circle, she couldn’t help but notice how there were significantly more portraits of ponies present than actual living ones. Each face drained of colour, with a single crimson X scored through them, as if they needed even more reminder that they were no longer alive.

“So, do you know who did it?” Maud asked in a whisper when she took her place to the right of Pinkie.

“Not who,” Pinkie admitted, “but I’m starting to get a good idea as to how.”

Maud gave a small nod in response, turning her attention to the centre pool. As the runes beneath Pinkie flashed and the railing ascended around her, she opened her saddlebags and placed the two books and jar onto the bench before her, making sure to separate the scrap of paper from the cover of the first book. Glancing up she noticed Rarity remove the blue feather as well as Octavia glancing into her own saddlebags without actually removing anything.

“Well aren’t you all a barrel of laughs today?” the Mastermind began, receiving only silence in response. “Really? No smart ass remarks? You disappoint me, I’m almost glad this whole ordeal will be coming to an end soon.”

“Any reason you’re so confident of that?” Octavia asked casually. “Besides the fact that by the end of this there will only be four of us left.”

“Let’s just say I have a good feeling about the whole thing,” the Mastermind replied in typical enigmatic fashion. “Yes, I think these next couple of days will be our last together… for most of us that is.”

“Can we skip this part?” Pinkie requested. “I’d like to get a move on.”

“Of course, I wouldn’t want to deny you the thing that makes you so happy Pinkie Pie,” the Mastermind agreed in a slightly amused tone. “Now, I call this trial to order.”

Trial 5: Rainbow Dash

“It’s hard to believe that after everything we’ve been through together,” Rarity began forlornly, looking between the portraits of Rainbow Dash and Applejack. “That half of us are gone.”

Pinkie nodded, she knew Rarity was referring to the Elements of Harmony.

“I never thought we’d fall apart like this,” Rarity finished, staring down.

“We should get started,” Maud suggested after a moment of silence. “So Pinkie, Octavia and I discovered the body around… three hours ago.”

“We noticed rigor mortis hadn’t set in yet,” Octavia picked up, “so she must have died shortly before that.”

“We also know that she had locked herself in her room until about two yesterday,” Pinkie added.

“What has that got to do with this?” Fluttershy asked nervously. “Rainbow died today.”

“Yes, but the actual cause of death was…” Pinkie replied, searching for the right word, “unclear.”

Pinkie cast a quick glance over her shoulder at Rainbow’s body which was still where they had left it. When would the Mastermind try to spirit her away?

“We noticed that Rainbow had no external damage,” Octavia reported. “With the small exception of some shallow cuts on one of her hooves which we linked to her punching her bedroom window, presumably in an act of rage.”

“While there was no wounding,” Pinkie continued, “she did display a number of symptoms indicating some kind of internal disturbance. Excessive sweating, vomiting, dry mouth, dilated pupils, when we first found her she appeared to be clutching her stomach in pain.”

“So, what?” Fluttershy replied, sounding a little confused. “The killer poisoned her here?”

“Actually we don’t believe the killer was even present at the time of the death,” Pinkie explained before looking over to Rarity.

“I used my spell to check the area for disturbances,” Rarity picked up. “It looked like Rainbow was alone when she was here. She walked over to where Pinkie is currently standing from between those two statues…”

Rarity gestured to the statues of Luna and Celestia.

“Then she seemed to move around a lot in the one spot before she…” Rarity finished, trailing off awkwardly.

“That’s why it matters where she was yesterday and this morning,” Pinkie concluded, looking specifically at Fluttershy. “Whatever method the killer used, could potentially have been carried out during that time.”

“Okay, so how was she killed then?” Fluttershy asked. “Some kind of poison?”

“Quite possibly,” Octavia responded. “I would assume from the way she was clutching her stomach that it was ingested.”

“Well I can assure you she hadn’t eaten any of the food I offered her,” Rarity cut in quickly. “She was adamant in her refusal, although she might have accepted food from someone else…”

There was a quick succession of denials from around the courtroom.

“So where would this poison have come from anyway?” Maud asked. “The infirmary?”

“Oh I hope not,” Fluttershy whined. “It’s been so difficult to keep stock since we tidied it up, but I was sure nothing had gone missing.”

While the others began discussing this avenue of thought, Pinkie turned her attention to the books before her.

“Would anyone know what you call it when you heat a mixture up and sieve it?” Pinkie asked, glancing down the contents page of the first textbook she found.

“Um, filtration isn’t it?” Maud replied unsure.

“Alright carry on,” Pinkie instructed, finding the relevant page number and skipping to it.

The others carried on talking, although occasionally they would glance at Pinkie who had her nose in the textbook.

Filtration is a technique used to separate solids and liquids in a solution, commonly used to extract specific components from a particular subject.

What followed was several pages of different methods depending on what component exactly you were trying to separate. Pinkie scrolled through each of them, eliminating any that didn’t line up with the setup she had seen in the lab. One method finally caught her eye, a method of extracting alkaloids from plants.

Dry out plant sample and mash up…

That would explain the use of the pestle and mortar.

Place the plant material in acidified water…

Pinkie glanced at the scrap of paper with the letters ‘PH2’ scribbled on them.

Heat to 50 degrees Celsius for 24 hours…

The pot over the Bunsen burner, it would also explain why it had just been left to stew.

Upon filtering the solution, the alkaloids will be in the filtrate.

Keeping her hoof in the page she was reading, Pinkie flicked back a few pages, searching for the definition she was sure she had seen.

Filtrate: the fluid resulting from the process of filtration.

Pinkie flipped back to the other page and leaned back.

So somepony was trying to separate the ‘alkaloids’ from a plant in the lab, and this mush I found was the solids leftover. The dark colour would correlate with Rainbow’s vomit, perhaps this was the poison she was made to ingest.

“Does anyone know what alkaloids are?” Pinkie asked aloud, interrupting the others from their ongoing debate about the infirmary.

“Alkaloids?” Fluttershy repeated. “They’re a toxic component found in plants… and some other stuff. Why?”

“Because I don’t think the poison came from the infirmary at all,” Pinkie explained, receiving a few raised eyebrows in response. “You see I came across an experiment setup in the lab earlier, and when I came back to check on it during the investigation, I found that it had been… altered. The book I found next to it explains it was a process of separating alkaloids from plant material. If what Fluttershy says is true, then the poison must have come from the lab, not the infirmary.”

“Interesting,” Octavia replied. “I hadn’t considered that, I wouldn’t know a thing about plants.”

“Fluttershy, weren’t you working in the lab?” Maud asked curiously. “Did you see this experiment that Pinkie is talking about?”

“What?” Fluttershy said, suddenly panicking. “No, I… wait, did it have a burner?”

Pinkie nodded.

“Oh goodness!” Fluttershy exclaimed. “I did see that, but I didn’t know what it was for so I just ignored it.”

“So what plant was used?” Rarity asked. “There’s probably thousands in that lab, and I’d bet most of them are dangerous in some shape or form.”

“Well I did find another book,” Pinkie explained. “It’s the same book Derpy learnt about curare from, and I found it hidden under Soarin’s bed.”

“What on earth was it doing there?” Maud asked, bewildered.

“The killer must have tried to stash it away,” Pinkie proposed. “Although it was a rather odd choice of hiding place.”

“I thought that book was still in the library,” Fluttershy pointed out.

“That’s right,” Rarity agreed, “but all the books were put away, so it would be easy for one to go missing. Still, what plant was it?”

Pinkie opened the book, her eyes scrolling down the contents, but this time she was looking for something in particular.

“Actually Rarity,” Pinkie said when her eyes fell on it. “I think it might have been the very plant you warned me about this morning.”

“I warned you about?” Rarity repeated, sounding confused. “You mean… Deadly Nightshade?”

“Exactly,” Pinkie confirmed, turning to the right page and holding it up for the others to see. "We already know that plant is in the lab, but what’s more, this book says the lethal effects are caused by an alkaloid called Tropane.”

“Well that seems inarguable,” Octavia stated.

“So the killer found that book in the library,” Maud summarised, “learnt about the effects of nightshade. Tidied the other books away to cover up the fact that they took that book with them. Then using the other book as a guide, prepared the poison in the lab, which they somehow managed to slip Rainbow Dash, causing her to die not long after.”

“Pretty much,” Pinkie agreed.

“What if the killer learnt about the effect of nightshade from what Rarity told you this morning?” Maud suggested.

“No, the solution takes a full day to prepare,” Pinkie explained. “The killer would needed to have started sometime yesterday.”

“So we now know where the killer got the poison,” Rarity interrupted, “but that still doesn’t explain how they managed to get Rainbow to ingest it, assuming that really is how it was delivered.”

“Well if the poison wasn’t finished until sometime after I left the lab this morning,” Pinkie began. “Then we have to wonder where Rainbow was after that time.”

“We already know she was seen around the upper floors of the central chamber by Maud on a couple occasions,” Octavia pointed out.

“And I did find her feather in the throne room,” Rarity added, holding said feather up.

“Maybe we should look into where everypony else was at the time,” Maud proposed. “Octavia and I were busy in the office until shortly before we discovered the body, we never saw Rainbow Dash on that floor and we didn’t see her when we went to the library together.”

“That’s where we were coming from when we ran into you,” Octavia added, nodding to Pinkie.

“Well I was in the infirmary because Fluttershy wanted to make sure I hadn’t hurt myself after Rarity knocked me over,” Pinkie explained. “Although… Fluttershy, where did you disappear to? I was waiting for ages for you to come back.”

Fluttershy froze for a split second; Pinkie could almost see her mind working at a hundred miles a minute behind her eyes.

“I needed to go to my room,” she replied quickly. “I’ve been keeping some of the painkillers there in case there was another incident in the infirmary.”

“I take it you didn’t find any?” Pinkie asked suspiciously. “Because you didn’t come back with any.”

“Um, no, I must have misplaced them,” Fluttershy stated meekly.

“Alright,” Pinkie said slowly before looking to Rarity. “What about you Rarity? Where did you go after I came down to the infirmary?”

“Well, when it seemed Fluttershy no longer needed my help…” Rarity began awkwardly, “I went to go find Rainbow Dash.”

Pinkie was taken aback.

“Did you find her?” she asked almost sternly.

“Of course not,” Rarity replied exasperatedly. “If I had I would have reported it earlier. No, I searched the whole ground floor and library wing before I heard the announcement and came running.”

Pinkie took a breath; she didn’t like how this was unfolding. Maud and Octavia were both out of the question as they had each other as alibis. Pinkie knew that she herself wasn’t responsible, that only left Rarity and Fluttershy. Pinkie didn’t want to believe that either of them had done this, but their explanations for where they had been were so flimsy, especially Fluttershy who had been acting odd for a while now.

Perhaps there was something Pinkie was missing, something she was overlooking. Her eyes scanned over her evidence, quickly picking out one piece. The scrap of paper with the PH number for the filtration experiment jotted down.

“Does anyone know…” Pinkie began, “what has a PH number of 2?”

The others all fell silent, contemplating the question. Pinkie was sure none of them would have an answer when at last Maud spoke up.

“Lemon juice,” she stated.

Pinkie nodded, as another piece suddenly fell into place.

“I know where the killer got the acid for preparing the poison,” Pinkie declared.

The others all stared at her in anticipation.

“Yesterday,” Pinkie began, “we ate salad for lunch. In that salad we had lemons…”

There was a brief moment of silence as the others mentally pieced it together.

“So the killer got the acid from the lemons,” Maud finished.

Pinkie nodded.

“Which means the killer had to be…

“Fluttershy!”

Fluttershy squealed and ducked down beneath her railing.

“It wasn’t!” Fluttershy exclaimed. “I wouldn’t! I couldn’t! She was my best friend!”

“But you did say yourself that at least she was with Soarin again,” Pinkie reminded her. “You’d also read this book on plants yourself, so even if you didn’t already know about nightshade, you knew where to find out about it. You were also working in the lab today, so it would have been easy to just ignore your experiment. You were also the one to take a plate of food to Rainbow’s room yesterday when she wouldn’t come out, you could have taken the lemons then without anyone noticing. And finally, if anyone could have convinced Rainbow to eat something it would be you, her childhood friend.”

“No!” Fluttershy wailed, tears streaming down her face. “Please Pinkie, you have to believe me!”

“Your intention might have been good,” Pinkie admitted. “Wishing to reunite Rainbow with her lost love, but the simple fact is, you killed…”

“No she didn’t.”

Pinkie froze midsentence, turning to face Octavia who stood in a thoughtful pose.

“Excuse me?” Pinkie asked, astounded.

“Fluttershy didn’t kill Rainbow Dash,” Octavia repeated.

“And how do you know that?!” Pinkie demanded.

“Because I know who did kill her,” Octavia replied. “And you do too; you just haven’t considered the possibility.”

“Haven’t considered the possibility of what?!” Pinkie demanded. “You know it wasn’t easy for me to just accuse my best friend of murder, and now you’re telling me someone else is responsible, and that I secretly know who it is!”

Octavia simply nodded.

“Well I know it wasn’t any of the rest of you,” Pinkie continued, “so unless you’re suggesting Rainbow Dash killed herself…”

Pinkie stopped, realisation hitting her in the face like a sledgehammer.

“She killed herself,” Pinkie whispered.

Octavia nodded.

“You’ve solved so many murders,” Octavia began, “naturally it was all you could think of when it came to Rainbow’s death. If you’d stopped for just one moment and considered that, just maybe, this one was different from what you were used to, you would have seen it for yourself.”

Pinkie just stared at her. It all made so much sense, why Rainbow was seen in the library and in the upper floors of the central chamber. Why she was alone in the courtyard at the time of her death, why she went to the place Soarin had died, why the book she had taken was in Soarin’s room. And of course the only one who could have made her ingest that poison… was herself.

“How did you know?” Pinkie asked, her voice weak.

Octavia reached into her saddlebags and pulled out a sheet of paper.

“I had no right to keep this from you all,” Octavia began holding the sheet out towards Rarity who levitated it over towards Pinkie. “She was your friend after all. But… I guess I was still testing you Pinkie. Always eager to see what you would do.”

Pinkie reached out and took hold of the paper when it reached her. Looking down she saw it was a letter…

Dear Fluttershy, Rarity and Pinkie Pie.

By the time you’re reading this, you’ll probably have already found my body. I wasn’t murdered, which I guess makes me a first in this damn game. Instead I took the easy way out. You might hate me for it, you might think I’m a coward… and yeah, you’d be right. I thought I could push through, I thought I could go on without him, but I just can’t. I never really understood the whole romance thing, I never got what you always saw in it Rarity. The only thing I cared about was being the best… until I met him. Soarin changed my life. Suddenly I didn’t care about winning or being a Wonderbolt, if it meant being with him, I would have given it all up in an instant. And that’s what I’m doing; I’m giving it all up so I can be with him again. But I don’t want you girls feeling sad about it.

Rarity, I know we never saw eye to eye on a lot of things, but then we were practically opposites. But know that I mean it when I say I wish you all the happiness and success in the world. You’re gonna make it big in Equestria, I just know it. Spike’s one lucky guy, I know you’ll be happy together. Tell Scootaloo I love her, tell her she was the best sister I could have had, tell her that if anypony is to fill my title as most awesome pony in Equestria, it’s her.

Pinkie Pie, I didn’t mean what I said, I don’t blame you. Soarin was one of the bravest ponies I knew, and I couldn’t have expected any less of him. What happened wasn’t your fault. Everything you went through was hard on you, not a day goes by I don’t wish I could have been there for you, could have protected you. We were once like two peas in a pod, but that feels like a long time ago. I know you’ve been through so much, I know that you’re still hurting, but never let go of that part of yourself, never stop smiling.

Fluttershy, I’m sorry for what I said. You are my closest friend; you’ve been by my side as far back as I remember. You’ve been with me through all the best times and all the worst times. I never regretted leaving it all behind to go to Ponyville with you, not for one second. You’ve given me and everyone so much; you deserve to be happy…

You girls mean everything to me; I know that together you’ll get through this. I’m going now; I’ll pay a visit to the throne room, say a few words to Applejack. Hopefully I’ll see her and Twilight on the other side.

Taking off for the last time, Rainbow Dash.

Pinkie set the letter down, faintly aware that at some point she had started crying.

“Pinkie,” Fluttershy began with a sniff. “What does it say?”

Pinkie held the letter up and Rarity hovered it over to Fluttershy. There was a long period of silence as Fluttershy read over the letter, breaking down into more quiet sobs before eventually relinquishing it to Rarity who reacted similarly to the two before her. Pinkie wondered how damp the letter would be by the end of it.

“I’m sorry,” Octavia repeated.

Pinkie didn’t have it in her to reply. She didn’t even know what she would say, or even how she felt. It certainly annoyed her that Octavia had knowingly lied and allowed Pinkie to accuse her dearest friend of murder. A part of her felt ashamed that she would ever jump to that conclusion without even considering the truth of the matter.

Rarity finally set the letter down, which appeared to be the signal for the Mastermind to kill the mood.

“How sad,” they announced, in a mocking tone. “Are you all ready to place your votes?”

“How do you expect us to vote for someone who’s…” Maud began.

“Exactly the same as you would vote for someone who was alive,” the Mastermind cut in, sounding impatient.

The dials lit up, Pinkie weakly turned it towards the spot which was now occupied by Rainbow’s portrait. The others followed suit, even Fluttershy so that soon the pool was filled with ghostly images of Rainbow’s face. Pinkie didn’t pay any attention as the clock hands appeared and did their little dance around the courtroom, only looking up when they settled pointing at Rainbow’s empty slot.

“Yes, the element of Loyalty had abandoned her friends of her own fruition,” the Mastermind said gleefully, earning a number of glares. “However, this leaves us with a bit of a pickle. Normally somepony goes to the block right about now, but with no murderer we’re kind of at a loss. I guess I could always…”

Pinkie couldn’t have been prepared for it. The explosion knocked her clean off her hooves, smashing into the invisible barrier around her. She slid down and shielded her head desperately from the raining debris. As the cloud of dust finally began to dissipate, she glanced up, seeing the others had taken similar actions in protecting themselves.

What the hay did the Mastermind do?!

Pinkie stumbled up, dusting down her dress before turning around to see what had exploded. She only had to turn slightly to the right before she understood, her jaw falling open.

The pedestal was all that remained of Cadance’s statue; the rest of her body reduced to dust and lumps of broken stone spread out across the courtyard.

“Equestria doesn’t really need a princess of love anyway, she won’t be missed,” the Mastermind said nonchalantly.

With that, the runes beneath them faded and the railings descended into the floor, leaving them all standing, staring at the crumbled remains of their Princess.

For a long time, nobody did anything. Nobody moved, nobody spoke. It was only when Pinkie was able to tear her eyes away from where Cadance used to be to the body of Rainbow Dash still lying a few yards behind her, that she moved.

Approaching the body, Pinkie leaned down and began trying to hoist her up. She didn’t have the strength to do it on her own however, and quickly collapsed. The she felt someone else take some of the weight. Looking up she saw Rarity and Fluttershy standing over her. Silently they all worked together to raise their friend up and carry her back towards the Castle.

Author's Notes:

An alternate title for this chapter was 'When Life Gives You Lemons'.
So who was right? Who figured out that it wasn't murder at all? Well our first winner is a six sided die... I mean, ClickClackTheBrony, however we also have Wolfe and WindSilver, Ultimate Eden Knight and Basic13, all four of which guessed it was a suicide, but made the slight mistake of assuming it was assisted by Fluttershy, only Davaba19 guessed suicide on its own. So we have quite a lot of winners today, maybe I'm getting predicatble.
Oh well, with only one chapter left I hope you're all enjoying it, you can expect to see the beginning of the end posted within a couple days.