A/N: Sorry this took longer than normal to get to you but I was working through the pain of the biggest hangover of my life. Yes, it's all my own fault but it was so much fun! At least, last night it was… Please review, if only so I have a reason not to keep kneeling at the porcelain altar… Someone help me…. Ugh…

To make up for the delay, it's even longer than normal. Let's see how many people actually make it through the techno mumbo jumbo… As usual, please please please review. I had real trouble with this one so I'd like to know what you all make of it!

Doctor Brennan marched in to the autopsy suite, Agent Booth matching her step for step as he flicked through a thick FBI file. Stopping at the side of the examination table, Hodgins brushed past with an armful of delicately balanced evidence bags as Booth put his hand out to lean on the side, receiving a look of frustration from Zach.

"Don't touch the table!"

Booth flinched as if he'd just touched hot coals. Offering up a sheepish grin, he turned to Brennan who was busy slipping on a lab coat and latex gloves.

"According to the base's security records, Agent McAvoy signed in as a VIP guest the morning of your lecture at… 6:47am. He was planning on getting breakfast, I guess."

Brennan frowned as she crossed over to the table of bones, the skeleton having been carefully laid out by Zach over night.

"A VIP guest? Does that mean that he was here at someone else's invitation?"

Booth flicked through pages, his finger running down the list.

"Yes. He was an official guest of Doctor Harwood's."

Booth swallowed hard. That sort of information would normally make her a prime suspect. But it was Katie… He tried to avoid the look in Brennan's eye.

Before she had a chance to speak, the doctor from the previous day entered the suite, blinking in surprise at the number of people in the room.

"Doctor Brennan, I wasn't expecting to see you all so soon."

"I apologise, Doctor… I'm sorry, I can't remember your name."

He smiled, though there was slight disappointment in his pale eyes.

"Doctor Reynolds, but please just call me Gavin."

He reached out to shake her hand as Booth stepped forward, his eyes narrowed.

"Any relation to trainee Reynolds?"

The doctor blinked rapidly behind his horn-rimmed glasses, a slow smile spreading across his face as he offered his hand.

"You must be Agent Booth. And yes, he's my son. He was at the lecture hall when you found Agent McAvoy's body. He's very upset, as are we all."

He shook his head slowly, obviously still shocked by the news. Brennan watched him, her eyes examining the architecture of the pasty complexion pulled taught across sharp features, his pale watery eyes reminding her of a vole. There was a definite family resemblance between the man in front of her and the twitchy recruit from the auditorium.

Doctor Reynolds crossed the room to a long table, sliding on to a stool next to Hodgins who was examining pieces of gravel under the microscope.

"I'm just waiting for the second body to arrive. Do you mind if I observe until then?"

Brennan moved round to the head of the examination table, nodding absently.

"Of course not, Doctor Reynolds."

He grinned excitedly, glancing at Hodgins with a look of childlike glee in his eyes.

"Oh goodie, a chance to see how the magic happens!"

Hodgins rolled his eyes skyward while Booth just tried to hide his laughter with a cough. Brennan shot him a look but Reynolds seemed totally oblivious.

Despite feeling slightly uncomfortable under the doctor's intense gaze, Brennan turned her attention to Hodgins.

"Any progress with the trace evidence?"

He hopped off the stool with a bag full of small stones.

"Yes, it's gravel."

Booth shook his head in disbelief.

"Ok, even I knew that."

Hodgins just ignored him.

"The trace left in the wounds on the victim's palms was obviously gravel, but on closer inspection, I realised that this was actually piedmont gravel which was very exciting."

It was Doctor Reynold's turn to chime in.

"I'm sorry, how exactly is gravel exciting?"

Hodgin's bit his lip for a moment, his knuckles tightening around the evidence bag before he continued, his attention purely on Doctor Brennan. Booth couldn't help but smile. He was starting to like Doctor Reynolds.

"Piedmont gravel consists of coarse stones carried from high ground by rivers and alike, often being distributed throughout smaller streams. When we first arrived at Quantico, I noticed there was a small stream on the edge of the obstacle course that was lined with these types of stones. However, the trace on Agent McAvoy's hands also included pine needles. When we arrived at the second crime scene, I noticed similar gravel lining the path to the right of the obstacle wall and what do you know, it's right underneath a pine tree."

Doctor Brennan nodded, looking at the small stones that Hodgins was waving at her.

"So both our victims were killed at the same place on the obstacle course."

Hodgins grinned at Booth as he triumphantly took his place back on the stool.

"I just broke the case, didn't I?"

Booth ignored him, obviously deep in thought.

"That's his killing zone."

Brennan frowned at him.

"A killing zone?"

Booth's head snapped up, his eyes automatically locking with his partner's.

"Yeah, somewhere that he feels safe, comfortable and secure. It would be somewhere he'd have scouted on numerous occasions, checking the rounds of the MPs or the amount of foot traffic for example. It's a secluded area hidden from view from the main buildings so it makes sense."

Brennan didn't want to think about how Booth knew about a killer's train of thought. She knew that as a sniper, he had been ordered to do things that haunted him to this very day, forcing him to become a federal agent in a noble attempt at redemption and absolution.

She blinked rapidly, turning her gaze on to her grad student who was busy looking through a thin manila file.

"Zach?"

"The victim's blood alcohol level was .28."

Booth's eyebrows practically shot through the roof.

"Point twenty eight? Are you sure?"

Zach nodded as Hodgins just stared at the rest of the group blankly.

"Is that bad?"

Zach offered his usual staccato response.

"Many physiologically active materials are removed from the bloodstream whether by metabolism or excretion at a rate proportional to the current concentration, so that they exhibit exponential decay with - "

Booth cut him off with an impatient look

"The legal driving limit is 0.08 and by 0.30, most people would be unconscious. So yeah, that's bad."

Hodgins nodded.

"See Zach, why couldn't you just say that?"

The grad student frowned.

"I did."

Brennan looked at her partner.

"Do the guards make a habit of letting drunks in to Quantico?"

Booth opened his mouth to answer but Doctor Reynolds beat him to it.

"I'm afraid to say that it's common knowledge that Agent McAvoy was an alcoholic. He retired from his post before they could fire him for it. He had become incredibly adept at hiding his lack of sobriety."

Zach looked up from the file as Temperance stared down at the bones in front of her.

"Doctor Brennan, the victim was in the process of metabolising a sizeable dose of analgesics."

Booth glanced at his partner.

"Translation?"

Brennan answered without even looking up from the bones she was examining.

"He was on prescription painkillers."

"Ok. Zach, try and remember that not everyone in the room gets the geek speak."

Zach ignored the agent.

"The victim had taken a large amount of morphine, Doctor Brennan."

Frowning, she turned to Doctor Reynolds.

"Did Agent McAvoy have any history of substance abuse?"

He shrugged.

"Not to my knowledge, though I know he suffered from back pain over the years."

Brennan turned her attention back to the skeleton in front of her, a gloved finger hovering above the spine. She waved Zach over.

"Do you see the low bone mass and the structural deterioration of the bone tissue?"

He nodded slowly, understanding what she was getting at.

"He had osteoporosis."

Brennan's eyes patrolled the bones.

"That would have caused this vertebral compression, leading to his need for narcotics."

Booth blinked rapidly.

"Huh?"

Brennan pointed at the spine in front of her.

"Agent McAvoy's osteoporosis caused his bones to deteriorate to the point that his vertebrae collapsed, much like a sponge collapses under the pressure of your hand. It would have caused a severe, band-like pain that radiated from the spine around both sides of his body. That would be why he was medicated on morphine and possibly why he started drinking."

Booth spoke without looking at Brennan.

"Bones, he was a field agent for twenty years and a soldier long before that. It's not always the physical pain you have to find a way to cope with."

She watched him then, his shoulders slumped as he stared at the file in front of him while playing with that same old poker chip, and her heart went out to him.

"I know, Booth. I understand."

He raised his eyes to hers, the look they shared saying more than they would ever dare to put into words. Brennan cleared her throat, turning to Zach.

"What about the bullet?"

"I ran it through the database here, Doctor Brennan. It came back to Agent McAvoy's service revolver."

She nodded slowly, her fingers carefully investigating a distinct impact to the back of the skull.

"For a man with such progressed osteoporosis, the smallest blow could have been fatal. However, the extent of damage from this head wound suggests a blow that would likely have killed a healthy man, creating a subdural haematoma and a relatively slow death."

She looked at Booth, the sequence of events beginning to solidify in her mind.

"So Agent McAvoy goes down to the obstacle course for whatever reason, though the back pain would suggest it probably wasn't to go for a run. Having already had a large amount to drink mixed with his morphine, he would have been easy to overpower, especially as the attack came from behind."

Hodgins stood, crossing the lab towards Brennan as he spoke.

"Dazed and dying, he would have fallen forward and broken his wrist as he hit the ground, creating the graze that filled with gravel and pine needles."

Zach nodded, stepping up to the plate.

"The subdural haematoma caused by the trauma to the head would have left him virtually unconscious, making it easy for the attacker to shove the screwed-up photograph and the ring down his throat."

The three turned to look at Booth as one, their faces expectant. He just shook his head at them.

"I thought I was the one who was supposed to do the assumptions."

Brennan grinned at him, patting him on the forearm.

"Well, we squints learned from the best."

He grinned back.

"Then tell me how Agent McAvoy somehow got from the obstacle course to the lecture hall almost a mile away…"

The trio frowned until Zach suddenly yelled out "Golf!"

Booth just stared at him.

"Golf?"

"I mean, golf carts. Like the ones we used to get to Hogan's Alley on the tour. You could easily put a body across the back seat to transport it."

Booth shook his head, pretending to be on the verge of tears.

"My squints are getting all grown up. Soon they won't need me anymore. I just hope I taught them well…"

The doors crashed open behind them, ridding Booth of the chance to tell the scientists to leave the cop work to the cops.

Two men pushed a gurney in to the lab, handing over the paperwork for Doctor Reynolds to sign. Even with the body bag closed, they could all smell the stench of burnt flesh.

The men left, clipboards under their arms as they chatted animatedly about the previous night's football game, while Reynold's surreptitiously switched on the overhead fan, sucking the worst of the smell away.

He unzipped the body bag, carefully removing the body with Zach's help, and laying it on the examination table with a grimace. He looked down at the corpse for a moment, his head cocked to one side as his eyes roamed up and down.

He pulled a dictaphone from his pocket and proceeded to take notes.

"The female victim's severe burns would suggest an incredibly hot fire, most likely due to the use of accelerants."

He leant forward, sniffing at the corpse.

"From the smell, I would guess gasoline at this stage, though samples will be taken for proper analysis."

On cue, Hodgins leaned in from the other side, taking cotton swabs from various sections of the remains. Reynolds began to carefully examine the clothing as he continued talking into the recorder.

"The most severe burns and likely source of the fire appear in the area around the right hip, implying this was the point of ignition."

He moved up to the head.

"Dental records will be checked to assist in the identification of the victim who is, at this moment, beyond recognition. The victim…"

He tailed off, his hand reaching out to the victim's neck. Gingerly, he removed a partially melted and distinctly sooty gold necklace.

"It appears the victim's name was Joy."

Brennan's eyes widened. She could feel Booth's gaze on her as she passed an evidence bag to Reynolds, not looking at the jewellery in front of her.

Booth crossed over to a computer on the far side of the room, searching for details on any recruits at Quantico with the name Joy.

All the time he was typing, one phrase kept spinning round his mind.

Two for Joy. Two for Joy. Two for Joy... The sick son of a bitch… Two for Joy.

Reynolds turned back to Temperance with a smile.

"Doctor Brennan, are there any observations you would like to make about the victim?"

She swallowed hard and focused on the job at hand.

"The victim is female, aged between 26 and 32, Caucasian and she used to be a ballet dancer, though she stopped sometime in her teens, replacing it with rock climbing."

Doctor Reynolds stared at her in disbelief.

"Seriously? You can get all that from this mess?"

She nodded, pointing at the victim's feet.

"Look at the arch of her foot. That shape is a result of the bones ossifying and muscles strengthening due to the use of pointe ballet shoes, enabling her to dance on the tips of her toes. The shape has begun to return to its original form however which would have taken years without practice. Instead, the shoulders have become more defined, indicating a great deal of upper-body work. What's left of the muscle structure would indicate rock climbing of some sort."

Reynolds just stared at her, his mouth wide open. Booth grinned at him as he returned from the computer.

"And there's the magic."

He returned his attention to his partner, his demeanour turning serious again.

"The only Joy on record at Quantico is a Joy Marshall, a trainee agent aged twenty eight. Of course, we'll need dental records to confirm it."

He locked eyes with Brennan.

"Bones, her minor at university was anthropology."

She just stared back at him, not sure what to say. In any other case that would just be a coincidence, but with all the evidence the killer had been leaving behind, it was clear that he had intentionally picked his victim because she was like her.

Two for Joy. Two of me.

Angela sauntered into the room, a sly smile on her face.

"I thought I heard your dulcet tones, Booth, so come on, don't hold out on me."

He blinked rapidly.

"What?"

She glowered at him, hands on hips.

"The killer. Who is it?"

He glanced around the room at the others, all of whom were staring back with blank faces.

"I know I'm good Ange, but I'm not that good."

"Don't flatter yourself, sweetie. I mean, who did Katie tell you it was?"

He frowned.

"I haven't spoken to her since last night."

"But she said she knew who the killer was and then she ran out of the room. I thought she was coming to tell you."

Booth felt the hairs on the back of his neck stand on end as he dug his cell phone out of his jacket pocket, quickly punching in Katie's number. It rang twelve times before switching to voicemail.

Snapping the phone shut, he turned to Brennan.

"She's not picking up."

Her eyes narrowed as she stared back at him.

"You don't think she'd confront whoever she suspects on her own, do you?"

Booth sighed, running a frustrated hand through his hair.

"She's a lot like you, Bones, of course she would."

He spun on his heel, pointing at Hodgins.

"You said the gravel definitely came from the area on the obstacle course where we found the second victim? That's his killing zone?"

Hodgins nodded.

"Yes but…"

Booth didn't hear the end of the sentence. He'd already run out of the door, Brennan right on his heels.

BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB

Together, the two of them charged through the trees, slowing down as they approached the clearing, crime scene tape flapping in the breeze ahead. Without prompting, Booth removed the gun from his ankle holster and passed it to his partner with a grim smile.

"Maybe now you'll get to shoot something. Just make sure it's not me."

She took the gun, following her partner into the open area, her heart pounding in her chest. After a few seconds, Booth lowered his weapon.

Nothing.

He threw his hands up in exasperation.

"I don't get it. Where is she?"

Brennan didn't answer. Turning to look at her, Booth waved an impatient hand in front of her face.

"Hello, Bones? Anyone home? We're meant to be looking for Katie."

She pointed over his shoulder. Turning round, Booth's eyes searched the area, seeing nothing until a slight movement caught his eye. Looking up, he saw that familiar face had turned a strange red, the lips displaying a tinge of blue as she swung under the branch, the noose tight around her neck.

Brennan swallowed hard, her face pale.

"I think we just found her."

A/N: Dun dun derrrrrrrrrr...! Is Katie really dead? Who is the killer? And can our favourite crime-fighting duo stop the murderous fiend before someone else dies? Tune in later today for your next hangover induced installment of (dramatic drum roll) The Man in the Lecture Hall! Though now I'm thinking it should be called 'The Man in the Lecture Hall and The Women in the Woods'... Kinda got a ring to it, dontcha think? Anyway, reviews, theories and general abuse are always welcome, begged for even, so please let me know what you think. I promise to update before the end of today!