Shout out ff1c, who correctly managed to find the link to Markin Rose from Colonel Scar's afterparty in Attack on Haven.Speaking of Commander Rose…

It took a few moments for everything to come back to life after the short shootout.
"Everybody OK?" Artemis asked, moving over to the office door.
"I'm fine" Holly replied.
"Affirmative" Cecily said.
Once Artemis opened the door to the office, allowing light from the corridor to flood the room so that they could see again, he noticed Holly staring at Markin Rose's leg.
"The injuries aren't healing" She said, a confused tone to her voice. "He should be able to heal them. What gives?"
"Fake leg" Artemis and Cecily said in tandem. Holly looked at them, then back at Rose.
"Very good fake leg too" Artemis said, walking over to where Rose was sprawled out on the floor and kicking away his gun. "And Cecily is a very good shot. It's just a shame Rose's wayward shot had to accidentally take out the lights."
"This isn't over" Rose groaned, jumping off the ground and throwing a punch towards Holly, who dodged it. With no purchase left on his fake leg, Rose collapsed back to the ground.
"I think you'll find" Artemis said, "This is very much over."

After handcuffing Rose to his own heating unit, Artemis sat down on a chair opposite to him.
"Help me understand" Artemis said. "You are a top-ranking officer in the LEP, with nothing on your record that would point to anything but high-quality police work. Why orchestrate an attack on your own station? On your own people?"
"It wasn't an attack" Rose grumbled. "It was a test! I don't know if you've realised, Fowl, but the line that was drawn separating fairies and humans has started to erode away, no thanks to you. Sooner or later humanity will once again have full knowledge of The People, and I don't need to tell you that the only thing that could result from that is war. This was a test to see if the LEP could stand up to the threat, and it showed that this institution is wholly inadequate!"
"13 officers died so that you could make a point" Artemis said sternly. "Now I see why Guns & Gangs had the highest rate of 'shoot first, ask questions later' style arrests."
"13 officers died so that thousands more won't!" Rose almost exploded, attempting to rattle the plasma bonds being used to cuff him. "I was doing the Lower Elements a favour! I am at the top of this job because I am not afraid to do what needs to be done. So what if I had to work with some unpleasant criminal entities? It was worth it. Look around you, the LEP has evolved, adapted because of what has happened. It is stronger than ever before, and this is just the tip of the iceberg. The LEP is just one line of this, one small fragment of this grand design. When the war comes, humanity best be ready because we will end them without mercy and with extreme prejudice."
"Tip of the iceberg? Interesting" Artemis said, inching his chair ever closer to Rose. "If you are planning something big, then you are even more out of your depth than I thought you were. What are you doing?"
"Oh wouldn't you like to know?" Rose spat.
Artemis laughed to himself briefly. "I understand now, oh why didn't I realise! Well because I hadn't heard your bravado militaristic speech before, but now I understand! That's why you want The Obelisk. You're preparing for war but Haven, and the Lower Elements in general, are not suitable places to fight a battle. The People are so heavily outnumbered, you need an advantage. You need to be prepared. That's why you want The Obelisk! Because you want to transform Haven into what would essentially resemble one giant military training world. You could build an army of fairies ready for war. The LEP was just the start, wasn't it? You were building up events like this so that the politicians and leaders would have no choice but to plunge the Lower Elements into martial law."

Rose, throughout all of this, remained silent.

"But you made one mistake. One massive, massive mistake. Because you can't do this alone. Even with the pulling power being Commander of the Guns & Gangs unit gives you, the contacts and the seized weaponry, you are still shackled to the LEP. Your every move is watched. You needed a facilitator, someone with who could make all of this happen on your behalf. An outsider who isn't a part of a system. You found Wyatt Munroe, who no doubt duped you into this by convincing you that he was a sympathiser. We know about Ferran Goy and Axl Snow, and the trip you took to the surface to 'retrieve' him. I have no doubt you met Wyatt Munroe in that time too, because it does not take 6 hours to retrieve a prisoner. I have no doubt either that Axl Snow was placed in MaxSec, somewhere his crimes should never have him placed, for the sole reason to recruit prisoners for your offensive on the LEP. It was detailed and it was extensive, but Wyatt was the kingmaker. He gave you everything you needed, and nothing more so than a belief that you were not only right in your opinions, but that you could actually win. I know he would have promised for things to happen on the surface, and I know he promised to get The Obelisk for you- which, granted, for a certain amount of time he did- but you should know that all of the promises are empty. He is the furthest thing from a sympathiser you will ever meet. He played you like a fiddle and you fell for it. That was the mistake that led to me getting onto this conspiracy being linked to my situation on the surface, but not the one that led me to you. No, that was you being so vain in believing you were untouchable- something no doubt Wyatt led you to believe- that you would hand write your letters to Ferran Goy. One simple event most people wouldn't even consider, is what blew your operation. It is over, Rose. You've lost. Artemis Fowl wins again."

Rose said nothing. He just stared into Artemis' eyes, a glazed expression that refused to betray any more emotion from the elf. For someone that had just been torn apart he looked defiant, unwavering. Artemis was very tempted to keep up the staring contest, until he heard the soft click in Rose's hand. His eyes darted towards it briefly, but long enough to spot the handheld explosive he was holding.
"OUT!" Artemis yelled, startling both Holly and Cecily. But they didn't need to be told twice when they saw Artemis make a sharp move for the exit. They were barely out of the door to the office when the explosive detonated, the fiery shockwave hitting them like a moving train, throwing them through the air like a ragdoll. They all came to a hard landing half way down the corridor in a haze of healing sparks. Behind them, the fire in what used to be Markin Rose's office began to blaze.

It didn't take long for the first responders to arrive. Even this late, Police Plaza had been on high alert ever since the attack. An explosion this big was practically a call to arms, but all they found was Artemis, Holly and Cecily, battered and bruised but otherwise OK.
"What in Frond just happened?" Colonel Julian Scar asked himself, transfixed on the raging inferno that used to be Markin Rose's office, whilst everyone else worked around him to try and get it under control.
"Markin Rose happened" Artemis rasped, before descending into a violent coughing fit. "We found the head of the conspiracy, and he not only killed himself because he knew we had already managed to get too much out of him, but he took his office with him so that we couldn't build any further leads. And to try and kill us, so that we couldn't talk, of course."
Scar looked at Artemis for a few seconds, then back at the fire.
"I take it you have proof of these allegations? Oh, what am I saying, you're Artemis Fowl, of course you have proof."
Artemis looked down at his tie to see if it was still intact, then nodded an affirmative.
"We need to get you cleaned up and seen to, and this fire under control, and then I need you in my office. I want to know absolutely everything."

Oh conspiracy, my conspiracy…