Author's Note: I'd like to thank phnxgrl, southerngirl1, Chkgun93 and TORONTOSUN for their reviews. TORONTOSUN: I'd forgotten about that episode until you mentioned it. This one is different, but I can see the similarity. Chkgun93: a Merry Christmas to you too. southerngirl1: we shall see... phnxgrl: I had a hard time coming up with the pop star's name because I don't generally listen to a lot of pop music. Was it a good name choice? We're starting this chapter on the following morning. Enjoy!

Chapter 29

Hotel security handed over a copy of their tapes for Tarmin's entire stay. Ryan had found a few tapes in the area and got started on them first thing in the morning. He had finished with the hotel footage and was now scrubbing the tapes from the area. Esposito was out with the CSU teams; they had expanded the search area in their attempts to come up with the murder weapon. Beckett and Castle set up the murder board with what little they had and then pulled up phone and financial records for the victim. Before they had gotten too far, Lanie called them down for the autopsy results.

"What do you have for me, Lanie?"

"An interesting one, that's for sure." Lanie opened a folder. "Cause of death is exsanguination. Ms. Martin's jugular vein was partially severed. Death would have taken a few minutes."

"What about the murder weapon?"

Lanie shook her head. "That I can't say for sure. The wound is a sharp-force trauma. Trace in the wound was more soot, flakes, and what looked like sand under the microscope. I sent it to the crime lab. I'm guessing it was transfer from the murder weapon."

Castle tilted his head back in thought. "Sand, soot, and black flakes. Maybe that will tell us what the murder weapon was stored in?"

"Maybe." Beckett took a close look at the wound. "It doesn't look like a very clean edge."

The M.E. shook her head. "No, Whatever the weapon is, it doesn't have a smooth edge, but it also wasn't serrated like a steak knife. In my opinion, the edge is straight but not completely sharp. Probably dull with defects."

Beckett grinned. "I'm guessing you've already updated your husband?"

"You would guess right. Just before you walked in as a matter of fact." Lanie returned the smile before handing the folder to Beckett. "All my findings are in there."

"Thanks, Lanie."

Beckett and Castle returned to the bullpen and resumed searching through the phone and financial records of their victim. Ryan had posted a still of their victim standing in an alley next to the hotel. From the photo, Beckett could tell Ms. Martin was alone. She sat down and picked up the stack of records, comparing the calls to a list of numbers belonging to Tarmin's family, friends, and creative team. So far, no incoming or outgoing calls for the past week belonged to anyone who was not on that list. No, wait, there was one. Beckett highlighted it and then added the number to the board.

"Hey, Ryan, are you busy?"

"Hold on, I'm hoping this person turns to face the camera." He was silent for another thirty seconds. "Nope, leaves the frame without looking at the camera. What did you need?"

"I need you to run a number for me."

Ryan pulled up the search engine. "Give it to me."

Beckett read off the number. "Is there a name attached?"

"No. Looks like a burner."

She wrote burner next to the number. "Who was so interesting?"

Ryan rewound the tape. "Him, or her I guess, with those clothes you can't tell the gender at all. I saw them go into the alley where Martin was killed a little before the victim does and then they leave several minutes later going the opposite direction."

"So you think this is the killer."

Ryan nodded. "Problem is they never face the camera. And that was the last one I collected. I'm going to have to get some more footage."

"Don't be afraid to give some to Tory."

Ryan printed out a still of their hoodie wearing suspect. "Yeah, I'll have her take over from here. What do you want me to do?"

"Background on the vic. Her bodyguard mentioned she was clean and had been for years after a friend died in prison because of drugs. Dig into that and see what you can come up with."

"You got it."

Esposito walked in. "Bad news. We couldn't find the murder weapon. Killer must have taken it with them and dumped it somewhere else."

Beckett put a notation next to "murder weapon" on the board. "Anything else turn up in your canvass?"

Esposito shook his head. "No witnesses, no one saw anything suspicious or saw anyone dump something suspicious. So I got nothing."

"Go help Ryan then. He's looking into the victim's past. He'll fill you in." Beckett's phone was buzzing. "That's weird. The crime lab wants to show us something."

Beckett and Castle walked into the crime lab to see a crime scene tech speaking with a younger, lower-level tech while she waited for them. She was tall with mid-length brown hair framing her charming face perfectly. Beckett recalled seeing her at a few crime scenes but couldn't remember if she'd ever spoken to her. The woman spotted them and ended her conversation with the other tech.

She extended her hand with a kind smile as they approached. "Hi, I'm Jo Danville. You must be Detective Beckett."

Beckett noticed the southern accent and decided she hadn't spoken to her before. "Yes, I am. Your accent sounds like it could be from the South. Georgia?"

Danville shook her head. "Alabama. 'Roll Tide!' Not a bad guess though. Follow me."

Danville led them to a workstation that had items on trays hidden under a cloth. Beckett realized now that they'd been called to the crime lab for a demonstration. She turned to Castle in time to see his face light up with excitement. Danville handed a sheet of paper to Beckett and had her read that first.

"Trace from the wound was carbon, fatty acids, polymer, chicle, and concrete granules?"

Castle looked confused. "What does that make?"

"The murder weapon." Danville produced a crude looking knife from under the cloth.

Beckett was surprised. "Where did you find it?"

"We didn't find it. I made this one. Allow me to demonstrate."

Danville pulled back half of the cloth to reveal a tray of items. On the tray were two foil wrapped sticks of gum, a bag of corn chips, one AA battery, a plastic coffee cup lid, and a napkin. Beckett and Castle glanced at each other. The items here appeared to be a cross between lunch and trash. They looked back to Danville to see she was smiling. Clearly, she was enjoying the looks of confusion on their faces.

Beckett shook her head. "You're going to have to explain."

"The traces are listed out of order of occurrence. First is the chicle, which comes from a gum wrapper." She stripped one stick of gum of its wrapper and picked up the battery. "Attach the wrapper to both ends of the battery and it creates a spark."

Danville placed one end of the gum wrapper on one side of the battery and then pressed the other end to the other side of the battery. A flame popped up in the middle of the wrapper and started to burn down both sides toward the ends.

Castle was excited. "That's so cool. I never knew you could do that."

Danville blew out the flame before it reached her fingers. "Next trace results are the fatty acids and carbon. That comes from the chips and napkin. What you do is wad up the napkin, then place the chips around it like firewood and light it."

Danville wadded up the napkin and placed it on a metal tray. Next, she opened the bag of chips and placed them around the napkin before stripping the second piece of gum. As before, she used the wrapper and battery to create a flame to light the napkin on fire. The napkin lit the chips on fire to create a steady flame.

"The chips act as fuel to keep the flame burning." Danville put on a pair of gloves and picked up the plastic lid. "The polymer trace is from the plastic of this kind of lid. You basically hold it over the flame to let the plastic get soft and malleable."

Slowly the plastic began to change shape as the fire heated up the plastic. Danville twisted it and shaped it over the fire to turn the lid into a stick of plastic with one end shaped vaguely like a knife edge. Castle kept leaning closer to the demonstration in awe of what was happening in front of him. Beckett couldn't blame him; that was mind blowing.

Danville removed the rest of the sheet to reveal a second tray with a dish of water and a block of concrete. "When the plastic is the shape you want, dunk it in water to harden," she dropped the sharpened plastic stick in the water and took off her gloves, "and then rub it against the concrete to finish sharpening the edge." She rubbed it against the concrete, leaving black flakes and a soot-like trace on the concrete and a pale powdered trace on the knife.

Beckett picked up the first "knife" they'd been shown. "That's it?"

Danville nodded. "That's it. We probably didn't find the killer's version near the crime scene for one of two reasons. One, the killer took it with them, or two they repeated the process to turn the knife into a plastic blob. Either way, we probably won't find the weapon at this point."

Castle took the knife from Beckett. "I am so added stuff like this to my Zombie Apocalypse kit."

Beckett saw Danville's expression change to confusion. "Don't ask. How did you know this was what the trace came from?"

"A cousin of mine researches and writes about prison culture. He sometimes has me help him figure out how various prison shanks are made. I like to test them on ballistics dummies and run the result through the machines so I have a database of trace results to reference just in case a strange one like this comes in."

Beckett was impressed. "Nice resource." She took the knife back from Castle. "Can we take this with us?"

Danville traded the display knife with the one she'd just made. "You can take the one I just made. My cousin and I made the other one. Let's just say I'm a little attached to it."

They returned to the bullpen with the knife to find the boys hard at work and Tory in the video room screening footage. The boys looked up when they saw Beckett and Castle reach the board. Beckett added another notation to the "murder weapon" slot and then checked out what the boys had found so far.

Carley Martin was from Hobart, Australia. She was the oldest of three and had started singing when she was six. She came to the US five years ago when a major record company signed her to their label. Since then, she'd been opening concerts for established artists, slowly making a name for herself in the music industry. She had two misdemeanor drug possession arrests in different states over three years ago. Soon after the second arrest, she entered court-ordered rehab. A few months after she got out, she had checked herself into another rehab facility. When she got out of her second rehab stay, her star began to soar. A few months ago she was having other artists open for her when she started headlining concerts.

"This is good work guys. Do we have anything on the friend?"

Ryan shrugged. "Maybe. The first time Tarmin was arrested for possession, there was another girl arrested with her. Her name is Amber Fisher. That time, both girls were charged with misdemeanors. 17 months later Amber was arrested again, this time with a lot more drugs in her possession. She was charged with a felony at that time. Tarmin had gotten out of rehab a month earlier and was opening a concert that night in the same city where Amber was arrested."

Castle bent over so he could read over Ryan's shoulder. "Did you say her name is Amber? Not was?"

"Yeah, she's still alive. Got out two weeks ago."

Beckett pulled out her phone. "Ryan, do you have the number the bodyguard called in the missing person report from?" He pulled it up and read it off to her. Beckett called the number. "Yes, this is Detective Beckett. We were doing some background on Tarmin to figure out if someone from her past might have had a reason to kill her. What was the name of her friend who went to prison?"

"Amber. Amber Fisher."

"Thank you very much." Beckett ended the call. "Amber Fisher is the friend. Tarmin must have lied to her bodyguard about how alive her friend really was."

Castle put Amber's name on the board. "Why would she do that?"

"Why she would lie about that is not really important right now. Ryan, can you pull up her photo?"

A/N: There was a character from a different (and no longer running) show making a guest appearance in this chapter. Did you spot who it was? Let me know if you did in the comment box below. Thanks!