A/N: So, this is over a week late, sorry. But it is longer than the past chapters so... forgive me? Hope you like this chapter, and I'll really try to get the next one out in a reasonable amount of time.

Sherlock got to Callie's first class early to speak with the professor. He had his questions prepared ahead of time and he asked each of her professors as the day went on. He even managed to hunt down professors she wouldn't normally see on a Tuesday.

Where did she sit? Who did she sit with? What was your opinion of her- as a student and as a person? Did anything about her change recently- her grades, her level of engagement, the things she said? Is there anything else you think is relevant? Are you sure?

The professors were no help, but Sherlock hadn't much expected them to be. Unless Callie Rogers had been a passionate student, there was no reason for any of her professors to know much about her personally. They all said that Callie was a kind and popular girl, an average student in terms of grades, but making up for it somewhat with her willingness to participate. In short, she was boring. She was a pretty girl who generally sat with a group comprised mostly of other pretty girls. Two professors said that, you know, now that you mention it she had been a little more withdrawn in class lately, and her grades had fallen a bit, seemingly due to a lack of effort. Most, however, glided over the last few questions, not wanting to become entangled in a police investigation.

He ran into the same problem each time he tried to talk to one of the friends she'd sit with. When he explained that he was helping the police with the investigation, they were touched and eager to thank him, but as soon as he tried to ask them questions, they suddenly had a class to run off to. Most of their answers were the typical platitudes one would expect in regards to a recently deceased acquaintance. It's so unfair- she was so sweet and funny! No, I couldn't imagine anyone wanting to hurt her! As with the professors, a few could be persuaded to admit she was acting weird in the past few months. Outside of class, they maintained, she was her normal self, but she had stopped coming to class regularly and when she did come, she didn't seem invested in it.

Asking if she was seeing anyone did yield some interesting answers. No one was exactly sure, but they all admitted that Callie had a taste for the bad boys. Thinking that anyone under suspicion of two murders would qualify as a 'bad boy,' Sherlock asked if they knew anything about John Watson, but suddenly the trail went cold. Almost everyone he asked said that the two seemed to like each other as friends only. "I always thought he might be into guys," one of Callie's few male friends added.

"Any reason for that?"

The guy shrugged. "Mate, if I was good at telling which guys were straight and which weren't, I would save myself a lot of heartbreak."

Around noontime, the campus became chaotic as people went to lunch, flocking to the canteen or to find friends. Sherlock, who had finished most of the interviews he wanted to, decided to follow the crowd. Callie had eaten in the canteen, so that's where he should be. Besides, he was putting it all together in the 'evidence' room of his mind palace. Callie had stopped caring about her classes. He remembered what John had said about Callie stealing his paper- "it was almost like she wanted to be expelled." The question was why? Had a boyfriend pulled her into something dangerous? Was she depressed? Maybe she was afraid of one of her exes and was losing sleep over it?

He grabbed whatever food he didn't have to stand in line for and then glanced around at the tables, trying to see if any of the people he'd talked to had congregated somewhere. He wanted to make sure he didn't miss interviewing anyone his victim had eaten lunch with. As he was scanning, he heard a voice behind him call "Mr. Holmes? Is that you?"

He turned to see none other than John Watson himself waving at him, alone at one of the smaller, four-seat tables along the wall. Unsure of what else to do, Sherlock walked over to him.

"What are you doing here?"

"Working on the investigation."

"Oh. Well, you can sit if you like," John said, clearly mistaking Sherlock's tray as a sign that he was on a break.

"I'm trying to find the group that Callie usually sits with for lunch."

"You found it," John said, kicking the chair across the table out to indicate that Sherlock should sit down. "We usually sit with our friends Katie and Marcus, but Katie wasn't ready to face classes yet, and Marcus is staying with her- y'know, to make sure she's okay."

"Those two keep coming up but I haven't met them. Seems they're avoiding the investigation."

"Poor Katie," John said, seeming genuinely unaware that Sherlock was implying suspicion rather than genuine concern. "She and Callie were best friends since high school- before that, maybe. She's absolutely distraught."

"You've talked to her, then?"

"A little. She says she knows I wouldn't hurt Callie- that it was probably some creep. I didn't tell her you thought it was a friend," he admitted.

"It is generally preferable that you don't divulge details of the case with anyone not affiliated with the investigation."

John looked at him with something resembling amusement for a second before asking, "How did you even get in here? It's only students and faculty."

"I am a student."

"Here?!"

Sherlock showed him his student I.D.

"Strange we've never met before. I suppose you're not doing medicine, then? Or communications- I take some of those classes too?"

"I'm doing criminal justice, biology, and sociology." Sherlock listed them off with a touch of smugness in his voice, used to people being impressed by his exhaustive list of academic successes. Not that he was trying to impress John Watson- this conversation was meant to be purely interrogational. It was Watson who was bringing it off track.

"Wow. Well, what kind of biology classes are you taking? You'd think we'd cross paths in anatomy classes, at least."

"I don't necessarily go to my classes. The point is to get the degrees. I'm focusing on learning Russian right now, actually."

"So what you just… show up to the finals?"

"I also write the papers sometimes- but this is off topic. I'm here to talk about Callie Rogers."

"What do you want to know?"

"Was she seeing anyone?"

"Not that I know of- but she wasn't very public about that stuff. She was never into serious relationships for some reason. I think she liked the excitement of seeing someone new- she always liked exciting guys, anyway. Katie would know better than I would."

"Were you ever involved with her in any way?"

"No, no I wasn't her type."

"When we last met, you mentioned something about her wanting to get expelled. Can you… elaborate on that? Was she behaving differently? Did she say anything?"

"No. If anything she seemed happier. She said a few times that she had a lot coming up but it's close to finals so that didn't seem out of the ordinary."

"…That's it?"

"I'm sorry, I really don't know too much. I have no idea why anyone would want to do that to Callie. I wish I could help more."

"That's what I find strange, actually. Why are you trying to help me? You're being awfully nice to someone who was just yesterday interrogating you under suspicion of murdering a close friend."

"Well, it's like you said yesterday. You're the only one who doesn't think I killed her. It's in my best interest."

"I still think you killed somebody."

"Zach? I figure I'll worry about that after all this stuff with Callie is done. Do you have any evidence- why do you even suspect me? It didn't seem like anyone else did."

"I have… significant personal reasons."

"Can you elaborate?" John asked, eyebrow raised, almost smirking at the opportunity to throw Sherlock's words back at him.

"This isn't a joke, Mr. Watson. I saw you."

"You saw me when?"

"Drowning Zachary Wells! I saw it happen, alright?"

John stared at him for a minute. "I… I have a couple of problems with that, Mr. Holmes. The first, obviously, was that it didn't happen The second is that if you did see someone drowning someone else, why you wouldn't tell anyone about it?"

"I was… drunk. And I didn't really know what was what until I heard that someone really had drowned but then I remembered seeing your face… Look, I know it wouldn't hold up in court or anything, but I know what I saw and I intend to follow up on it."

"I think you just got confused. I didn't leave my flat on Saturday night."

"Well. I guess if that's true you have nothing to worry about."

"I guess not."

By now, John had finished his food. Sherlock still had half a sandwich and a bit of rice left, but his high was wearing off and he was anxious for an afternoon line. Maybe that was why this conversation kept getting derailed. His head kept getting confused- all the information he was getting connected- a girl who liked dangerous guys, a sudden disinterest in academics- but it didn't seem to go anywhere. And he'd never dealt with anyone quite like Watson, who asked questions back, questions about Sherlock himself, no less.

"I'm a busy man, Mr. Watson- if you don't mind we'll move quickly through these last questions."

"Sure- and you can call me John."

"Did anything big happen in the past week- maybe around last weekend? Fights, big news…?"

"No."

"And how much of Callie have you seen in that week?"

"Let's see- didn't see her last Saturday. We hung out with Katie and Marcus on Sunday. Monday it was just lunch, Tuesday we studied together- in the library- and then had dinner. Wednesday and Thursday it was just at lunch. And Friday- the night before it happened- I went out for drinks with a few other friends and ran into her and Katie there. They left at about eleven, though. Don't know if they went straight home."

"Was she drunk?"

"She had a couple of drinks, but she wasn't out of control. Katie was fine, she wasn't drinking."

"Alright. Let's go back to that Sunday. So you were-"

"Excuse me," a voice interrupted. They looked up to see DS Loman standing beside the table.

"John Watson, you're under arrest under suspicion of the murder of Callie Rogers. You do not have to say anything but it may harm your defense if you do not mention, when questioned, something which you later rely on in court. Anything you do say may be given in evidence." He was grabbing John by the arm and pulling him up, attracting the attention of everyone else in the room.

"But yesterday you said I was free to go!"

"New evidence. Come on."

They walked off; Loman didn't acknowledge Sherlock once. Sherlock rushed to follow them, leaving his plate abandoned on the table. He couldn't get anyone's attention until he finally reached the police car parked at the front of campus, where Lestrade was waiting.

"What's going on?! Loman said something about new evidence?"

"We found the murder weapon in some bushes near the victim's dorm hall. Along with Watson's mobile."

"Were his fingerprints on the knife?"

"We've sent it to be tested. How did your questioning go?"

"Not too badly. Something was definitely going on with Callie- maybe her blog will help with that. I was talking to Watson again before you arrested him."

"Get anything useful?"

"On him? No. Do me a favor- ask him about that party on Sunday? Loman dragged him off before I could. I have a class…"

"No problem." He cuffed Sherlock on the shoulder amicably before walking back to the car, where Watson was already in the back seat. "I'll see you tomorrow, Sherlock," he called, getting into the driver's seat. "Rogers's funeral is on Friday, so if you want to examine the body yourself you should do it soon!"

Sherlock raised a hand in acknowledgement but otherwise watched impassively as they drove away. He was still anxious to get home and do a line or two, but there was one more thing he wanted to check. Usually he would get a cab, but the lake was in the middle of a park that you couldn't drive through.

It took him a half hour to walk from the university to the lake. He was working with a time frame of 10:00-10:30 with Callie, but he wasn't so sure about the time of Zachary Wells drowning. He could barely trust his account of what happened, he didn't want to set much store by his time frame. Maybe the drowning had happened earlier than he'd figured- or later, Watson might have been on his way back from killing Rogers. Sherlock pulled out the address he'd pulled from Watson's file. It took another half hour to walk to his flat.

He didn't bother sneaking inside, but he noted the security camera by the building's front door.

"Watson's building has cameras. Make sure to get the footage from Sat. night and let me know what time he left and when he came back -SH" he texted Lestrade.

After an hour of walking with no discernable trace of cocaine left in his system, Sherlock was exhausted and grumpy. He hailed a cab to take him the rest of the way home, wondering if it was time to consider John a suspect of both murders.