My first attempt at an action fic - bear with me! :)

"Get up, Lewis." Jace Herondale kicked the side of officer Simon Lewis' desk. "We've got a new case."
"Coffee?" Simon woke up from his slumber, a hopeful expression on his face.
Jace chuckled. "No - we've got to work our asses off on this one, or the mayor'll be out for my blood."
"Okay." Simon grimaced, but made an effort to sit up. "What's this one about? If it's important enough for the mayor to actually take it seriously, it must be..." He trailed off, raising his brows.
"Yes." Jace's smile disappeared. "It is. Six bodies were found. All horribly mangled. We might have a serial killer on our hands."
Simon shuddered. "I thought we'd seen the last of serial killers here when they got Valentine Morgenstern."
"Hmmm." Jace dropped a file on Simon's desk. "Look these over. I expect we'll head over to the coroner's in an hour or so. Pass on the message to the others, will you?"
"Sure thing." Simon muttered, twirling his pencil. "Where are you off to?"
Jace sighed. "That's sort of personal."
Simon's brows went even higher. "Cut the crap, Jace. We work together, but we've been friends for - what? Close on a decade and a half, isn't it? You can tell me."
Jace sighed again. "Okay - but don't call me crazy." He sat down in the seat opposite Simon's. "So, I got this note yesterday. Crazy thing - but I think," Jace paused, "I think it's true."
Simon gestured for Jace to show him.
The latter obeyed, taking it out of his shirt pocket and spreading it on the desk in front of them.
Jace Herondale. We meet again.
This ain't your town no more, boy.
Think you killed my father? Think again. He's comin', an' he's madder than before.
Signed, a Morgenstern that wishes you ill.
"Jace." Simon pushed it away. "This is so whacked - you can't possibly take this seriously."
"But I do."
"Jace!" Simon ran his hands through his hair in frustration. "Don't you remember all the crazy notes we got after that maniac Valentine was killed? This is just another one."
"It isn't." Jace responded serenely. "This is very different."
Simon stared at him as if he'd sprouted another head. "How?"
"I don't know."
"What do you mean, you don't know?"
"Shall we meet up with the coroner?"
"God, Jace."

"You'll notice the multiple lacerations here, and here."
The coroner, Tessa, wore her most serious expression - her hair screwed up into a no-nonsense bun.
"They're quite deep, so I'd suggest they were inflicted with a lot of force." She gave them a wry smile. "Death was instantaneous for this guy over here." She pointed at the newest victim. "But for the others..." She trailed off, shaking her head.
Jace looked grim. "What can you say about the weapon?"
"Blunt. Definitely not a knife." Tessa reached for a file on her desk. "I've also found a residue in the wound that I couldn't identify. The lab's wracking their brains trying to figure out what it is."
"Whoa." Simon glanced at the bodies. "So...if they're all pretty much killed the same way...that means we do have a serial killer on our hands?"
"I can't say for certain - we still have to run a few more tests, but I'd assume so."
"Thanks, Tess." Jace gripped Simon's shoulder, shepherding him out.
"So?" Simon crossed his arms, peering up at Jace. "You've got that look on your face. What do you think happened?"
"It's a hunch."
"Your hunches end up being right more often than not, so spill."
Jace hmm'd loudly. "Remember the Valentine Morgenstern case?"
"Jace." Simon groaned. "Let it go."
"No, no - hear me out." Jace replied impatiently. "Remember how old Morgenstern was devising his 'perfect crime' theory? He didn't have enough time to complete his research, because he got caught. Well...what if he did?"
Simon sighed expressively. "Jace Herondale - let it go. This is nothing. This isn't even the 'perfect crime'. This is a basic crime. A couple of dudes get slashed. Big deal. Sooner or later, we're gonna catch the dudes who did this and put them away for a looong time." He patted Jace's arm. "Nice of you to remember that old idiot, though."
Jace hmm'd again. "I'm not too sure of that, Simon."

"Nice of you to join me, sister." Sebastian slipped an arm around his sister. "As you can see, I've been doin' a little experiment. Would ya like to see?"
"Considering the fact I did most of the research for this," Clarissa replied, drily, "I think I deserve that honour. At least."
Sebastian laughed. "Follow me to the lab." He held out his hand theatrically, and Clarissa took it with a laugh.
"Those right there are my beautiful specimens." He presented them with a flourish of his hand. "Crossbreeds. Ain't they beautiful?"
Clarissa stared down at the greyish-green lizards with interest. "Small. They're too small, Sebastian. You didn't use my data, did you?"
"Ah, beautiful sister - there you're wrong!" Sebastian laughed. "I did. I took more than your data. I worked on it. Those creatures there," He pointed at them in their cage, "Have the brainpower of a primate. Would you have thought of it, dear sister? Would ya?"
Clarissa smirked. "True. But I was aiming for practicality. How practical are these creatures? Can they still follow orders?"
Sebastian's manner became a bit more withdrawn. "That - I...I'm workin' on it."
Clarissa tossed her red curls over her shoulder. "You always screw up somewhere, don't you? Let me do it next time."
She left, slamming the door behind her.
"Clarissa!" Sebastian flung some papers at her retreating figure. "Damn her, so f-ing high-and-mighty." He stared at the lizards in the small cage. "You ain't useless. Don't you listen to my sister - ya hear me?"
One of the lizards stared at him, cocking its head intelligently.
"You understand me - don't ya?" Sebastian stuck one of his long fingers into the cage, stroking its head. "We'll show 'er. We'll do it. And then we'll show my daddy-o what we can do, won't we?"
Sebastian chuckled, stepping away from the cage and back to his desk. He glanced down at some of the paperwork and made a face.
"Clarissa's calculations. Clarissa's data. Clarissa's research." He looked at the lizards in the cage. "Everything's hers. Everything..."

"So, you'll be glad to know the lab finally identified that substance in the victims' wounds." Tessa bounded into Jace's office.
"And?" Jace put down the case files that he'd been reading. "What is it?"
"It's not so much one thing as it is a mixture." Tessa looked somewhat confused. "I'd call it a cocktail of various venoms. It's almost like someone's extracted venom from half a dozen venomous snakes and mixed them together."
Jace frowned. "And you found this inside the wounds?"
"Yes."
Jace stared up at Tessa. "Why would someone slash someone several times if they'd already coated their weapon with toxins? Wouldn't one wound suffice?"
Tessa shrugged. "Hey - we do the lab work. You guys figure out the "how", the "why" and the "who"." She spun around and took off, waving at Simon as she passed his desk.
"Well?" Simon gestured in Jace's direction. "What do you make of that?"
"I think," Jace replied, leafing through the papers Tessa'd left, "I think that it's too convenient for this to be unconnected with the Valentine Morgenstern case. And," He rushed on, seeing Simon's face, "You'd be happy to know that the old Morgenstern was a herpetologist before he became a certified loon."
"What does that have to do with anything?" Simon scoffed.
"Morgenstern would kill his victims by injecting them with snake venom he'd harvested from his nasty little pets." Jace rapped on his table for emphasis. "I think we've found our man."
"You're missing one little thing." Simon growled.
"What?"
"He's been dead for the past fifteen years."

"Sit here, Clarissa. Here - next to me."
Clarissa obeyed, sitting beside the old man in his long, dark cloak.
"How are things downstairs? Is everything well? I haven't been informed of the proceedings for so long." He seemed eager for any news she could give him.
"We had a slip-up." Clarissa reached into the breast-pocket of her jacket for her pack of Marlboros. Lighting it, she took a long drag before answering, "My brother is an idiot. He likes to think he's smarter than me. That he can do things his own way."
The old man looked sympathetic. "It always is that way - when one sibling is so much brighter than the other."
"It's not a question of brightness." Clarissa exhaled, blowing out an even smoke ring. "It's a question of obeying orders. Seb likes to experiment, to invent new things. But we all have work to do." She examined her long, black nails with their silver nail-art. "I, too, have work to do."
"In what way?"
"Nothing serious." She laughed. "Some fumbling detective has found out more than he should. Another blunder of my brother's, of course." Clarissa smiled at the old man. "Nothing to worry about, Father. I'll take care of it."
"I know you will, my dear."

So that's that! :) Like it? Hate it? Comments work wonders (hint, hint).
Anyway, let me know what you think!