Edited on December 30th due to incorrect characterization
They walked. They asked Twilight questions. They observed the alien town as they passed through.
Twilight made sure that Patches was between herself and Bill.
“Victim’s name?” Patches asked flatly.
“Her name is Amethyst Star. Was. I still can’t believe she’s…”
“Did you know the victim?” he asked, writing the name down in his notebook.
“I did. I went to school with her. I wasn’t close…”
“Victim’s occupation?”
“She was still just a student.” Twilight hadn’t thought about this before. Amethyst was so young.
“Were there any witnesses to the murder?”
Twilight didn’t answer right away. Her eyes were closed and she was breathing heavily.
"What kind of trees are these? They're pretty."
"Bill, remember when I broke your nose for asking stupid questions?"
"Yeah. Why?"
Patches knelt over the violet ex-pony. Twilight stood looking over Patches' shoulder. Bill was trying to figure out how to use straw to staunch the blood from his nose.
Patches lifted Amethyst's head, exposing her neck. He found the cause of death. Twilight had to look away.
At the base of Amethyst's throat was a gaping hole. The skin around the hole appeared scorched. Her expression told of the pain she endured in her final moments. Patches stuck his nose into the hole and breathed deeply. Twilight tried to look again at this moment and almost wretched at what she saw. What he smelled confirmed his suspicion that the burns were caused by some kind of corrosive chemical.
"I'm glad you didn't move her. It'll help us with the forensics. But seriously, why didn't you take her to a doctor?"
"There was smoke coming out of the hole in her neck. We thought it was dangerous. We had no idea what to do. We did call a doctor, but by the time he came she was gone, and since it was a murder I told everypony to leave the scene alone."
bang
Twilight turned quickly to face the noise. Patches gave her credit for not screaming. He'd known women under considerably less emotional stress to jump and scream at sudden noises. He turned to Bill, who was looking at the balloon he'd stepped on. The barn was littered with balloons, ribbons and paper hats.
"When you sent everyone home, did you note who all was at the party?"
"It was Pinkie Pie's party. She'll know who all the guests were"
Patches raised his eyebrows at the strange name. He stood up.
"We won't know what was used to kill her until we do an autopsy. Before that, I'd like to study the state of the barn exactly as it is right now."
Without a word, Patches and Bill went about their job of recording precisely the state of the barn. They were careful not to step on any balloons or even disturb the hoofprints on the straw-covered floor.
Twilight stood still, not wanting to interfere with the two men's work. She regarded their activities with deep fascination.
"Why would somepony do this?"
"There are three causes of murder", Patches replied, "Madness, money or revenge".
"I don't think a sane pony would do this"
"Maybe so, but my guess is that this was a revenge killing. Dangerous, uncommon chemicals. It was done in a public place, but it looks like it was planned ahead of time. And look at her. That was a horrible death she went through. Whoever did this really wanted to see Amethyst suffer."
Twilight was foreign to the idea of bloodlust. Nevertheless, the concept of wanting other than the best for those around her opened up realms of possibilities about how ponies could act towards each other. She was reminded of her first encounter with Zecora.
Bill used his measuring tape to record how far Amethyst was from each of the four walls. He then sneaked up behind Twilight and, starting from the base of her tail, quietly ran the tape along her spine, up her neck and up to the front of her nose. When the tape became visible to her, she quickly glanced around and was shocked at Bill's measuring her without her knowledge.
"What do you think you're doing?"
"I need to know how long a pony is while standing normally."
"You know it's not right to...measure a pony without asking, right?"
"No, it isn't."
"SO WHY DIDN'T YOU ASK?"
"You would've said no if I'd asked" was his excuse. He hastened to the other side of the barn.
Twilight groaned in exasperation.
"Bill, stop bothering the purple pony"
"My name is TWILIGHT SPARKLE!"
"I don't think Bill knows that"
Bill didn't appear to be listening. He was counting the rafters.
Patches examined the doorframe, and found a black spot. He smelled the same chemicals he had smelled on Amethyst.
"Hello, it appears our culprit left rather clumsily"
Out the door the trail continued; there were telltale splotches in the dirt showing exactly where the killer had walked.
The trio stood at the edge of a forest. The trail led into it. Patches and Bill were about to step in when Twilight stopped them.
"Wait. Before you go in, you should know what that is. That's the Everfree forest. It's not natural in there. Trees grow by themselves, and clouds move...by themselves"
Patches and Bill both blinked.
"So what's natural to you, then?"
"Not that!"
"Patches, she's right. There could be dangerous animals in there.
Like Lions. And Tigers. And Bears"
"Shut up."
Patches looked at Twilight
"We're going in. Bill, find the trail."
"Trail's gone"
The splotches had gotten fainter farther from the barn. At the edge of the forest they were invisible.
"Do you know how to track a pony in the woods?" Twilight asked. She was fine entering the forest when she was following the path to Zecora's house, but she was nervous entering the foliage at some random point.
"If we have to. First I'd like to try a different method."
Patches produced from his trenchcoat pocket a pristine white baseball. It was signed by ice hockey legend Bobby Orr, and so had no value so far as Patches could ascertain. He held it to his mouth, whispered "Tibet", and pitched it high into the air, over the trees, deep into the woods.
"Bill, go get it."
"Okay. I will."
Bill darted off into the thick trees. Patches and Twilight followed.