by Ken Goddard
“I tried all of the primary colors first,” Archie said quickly, “and there’s no good reason—or at least none that I can figure—why the sensor module would need to see the dots in color anyway. But it was the vendor who made the suggestion, so I tried the primaries, just to see what would happen. And when nothing much did, I ran the entire spectrum through the module on the second pass, just on a hunch, and the bright pink seemed to…work.”
“Clearly another sensitivity issue,” Warrick said, trying to keep a straight face. “I don’t know what it is about you, Arch, but you do have a knack for getting things to work.”
“And Nick?” Grissom asked, deciding that the young computer technician had suffered enough; or at least enough for the time being, he amended.
He’d also remembered, finally, that he’d come into the conference room for a specific purpose.
“Nick was heading back over to the garage, to give Sara a hand,” Archie said. “And I’m really sorry about the call-in earlier. It won’t happen again, I promise. And I will try to get the sensor module to acknowledge another…uh…color. I do realize that bright pink locator dots on a shooting reconstruction layout could be a little…much for a courtroom presentation.”
“Or, maybe just not quite…enough?” Grissom suggested with a shrug as he turned and headed toward the door.
He was halfway out the doorway, deep in thought again, when he suddenly stopped and turned back.
“Thanks for getting us back on track, Archie,” he said firmly. “I’m grateful for that.”
“I’m glad I could—,” the computer tech started to say when Grissom interrupted.
“And when you and Warrick get all of those laser scans and digital photos loaded into the program, I want you to take a look at some of the photos I took up on the mountain. I have another 3-D trajectory problem that I’m going to need you to help me figure out.”
Grissom was heading toward the garage, the germ of an idea beginning to take solid root in the back of his mind, when he glanced over at the analytical chemistry lab and saw Sara sitting in front of the X-ray fluorescence spectrometer with a pair of sample vials in her hand.
“Hi, how are you doing?” he asked, coming up beside her and gently patting her shoulder.
“Worn down, hungry, grinchy…and a few other things that are best discussed outside the office,” Sara replied, looking back over her shoulder and giving Grissom a tired but affectionate smile.
“I thought you’d taken over Greg’s work because you’d hurt your arm,” Grissom commented uneasily as he quickly looked around the instrument room to confirm they were alone, wondering as he did so if he had any idea at all of who was working where on this case anymore.
“I did,” Sara said as she set the vials on the lab bench. “But all the test-firing went real fast once Catherine got Sergeant Gallager to do the shooting. So, I gave Greg back his original job on the grill and radiator so that I could run all these trace metal swabs I took from the impact holes through the XRF. If I can figure out which holes are from the mostly lead pellets and which are from the copper-jacketed bullets, I think we’ve got a fighting chance to isolate the individual shotgun patterns.”
“Really?”
“I think so,” Sara said as she picked up another pair of vials, each of which contained three gray pellets. “We caught another break with the shotgun ammo. You remember those two boxes of buckshot rounds the state narcs used to fill their pockets before they loaded their shotguns…the ones that had two different batch dates?”
“Yes?”
“Well, it turns out that the pellets in the later-dated box contain almost four percent antimony—which is a new buckshot composition the company put out strictly for law enforcement, to harden the pellets—whereas the pellets in the earlier box have only trace amounts of antimony.”
“And you’ve tested how many standard knowns so far?”
“Three pellets each from three rounds selected randomly from the remaining ammo in both boxes.”
Grissom thought for a moment. “And what’s your standard deviation so far?”
“Point-oh-two percent.”
“Let’s go with it,” Grissom said with a smile. “How long will it take to run all the swabs?”
Sara winced. “Maybe another three hours, if everything goes okay. Simple work, but slow. We sure could use that auto-sampler.”
“I’ll remind Ecklie that he’s been sitting on our requisition for three months now,” the CSI supervisor promised. “But you know what he thinks about auto-samplers in general.”
“How can we trust a machine to never make a mistake when they’re programmed by humans,” Sara repeated from memory. “Is he ever going to get over that?”
“Probably not,” Grissom said. “But then, too, maybe he shouldn’t. There’s a lot to be said for going back to the basics.”
13
WHENGRISSOM FINALLY GOTto the garage, he found Greg on his knees in front of the truck grill, facing what now looked like a porcupine array of dowels, and Nick setting up a digital camera on a tripod.
“Do you and Warrick need more photos of the truck?” Grissom asked.
“Actually, what we need are better photos taken under controlled lighting conditions,” Nick said. “Warrick and I are pretty well convinced it’s the uneven lighting from the strobes and headlights out at the scene—mostly the reflective glaring—that’s causing the program to either mismatch the reference dots, or ignore them completely.”
“And you’d just as soon not have to resort to Archie’s color scheme, if you can find a way around it?”
“That too,” Nick admitted with a smile. “But for me, simple usually works out being better.”
“That’s what I said to Sara,” Grissom replied absentmindedly as he stood behind Greg for a few moments, watching the young CSI try to figure out which of the many holes in the radiator matched the one in the grill that he’d already run a dowel through.
“Did she tell you about the positioning mistake we discovered on Officer Grayson?” Greg asked, looking up from his work and blinking as if he’d just realized that Grissom had walked into the room.
“No, she didn’t.” Grissom replied. “What kind of mistake?”
“Well, I guess it wasn’t so much a mistake; more like the guy just didn’t realize where he was when he started shooting. It wasn’t all that clear in the dirt and sand impressions around that rock, and I guess no one else really saw where he was at because of that big boulder being in the way.”
“So, there was no confirmation on Grayson’s position from anyone else?”
“No, just his recollection, which seemed okay at the time because he was being so cooperative,” Greg said. “But when I gave Catherine the ejection pattern results from all the weapons, she said that Grayson couldn’t have been where he said he was during the shooting, because the four ejected casings from his Sig wouldn’t have ended up where they did.”
“And where was that?” Grissom asked.
Greg thought for a moment. “He was out in the open and moving back toward the ‘guy facilities’ boulder the entire time he was shooting.”
“Instead of immediately taking a barricade position, which would have seemed a much more logical option if he was expecting the arrival of a dangerous drug dealer,” Grissom pointed out.
“I called him on his cell a few minutes ago and asked him about that,” Greg replied. “He said it all happened real fast, and his memory is a little fuzzy. But he definitely remembers quickly zipping his pants up when he heard the truck coming, and walking toward the dirt road to see what was going on…and then grabbing for his pistol when he got caught in the truck’s headlights…and starting to shoot at the tires when the truck swerved away and headed straight for the camp.”
“Which would make sense—about not barricading himself—because he wouldn’t have felt as directly threatened as the others, once the truck swerved away from his position,” Grissom said, mostly to himself, as he stared at t
he hoisted truck’s flattened tires. “Instead, his movements suggest he was upset at having been caught off guard, and was trying to make up for it.”
“And because the truck was already past him when he started shooting,” Nick said softly, starting to understand where Grissom was going, “he had to have been very limited in what he could shoot at. Otherwise, from his position, he’d have been putting rounds directly into the camp.”
“Which probably limited his targeting to the rear tires, and only for a short time period,” Grissom added.
“That would have been roughly when he and the truck were lined up with the ‘female facilities’ boulder…which also means Grayson could have been the source of the bullet that hit Jane Smith,” Nick finished with a smile of growing awareness.
“Exactly,” Grissom said. “Can you reinflate these tires?”
“Not the front ones,” Nick replied. “They’re too shredded. I’d never be able to get the patches to hold at anything like standard tire pressures. But the back ones only have a few holes in them. Yeah, sure, I can get them patched and reinflated. But how are we—?”
“I’m going to need a 2-D overhead scan of the campsite that includes where the truck first came off the main road and turned toward the camp, and where it came to a stop,” Grissom said, his mind racing, “as well as the starting and ending positions of all six shooters…all projected up on this wall,” he added, pointing to the bare white wall on the opposite side of the garage.
“Only the 2-D scan?” Nick asked as he reached for his cell phone.
“That’s all we’ll need right now,” Grissom said; “that and a calculator or laptop computer we can use to run some trig functions.”
Nick paused. “We’re going to usetrigonometry to solve this?”
“Going back to the basics,” Grissom said. “Do you remember how to use the functions?”
“I—uh, think I’m going to get Warrick over here,” Nick said as he returned his attention to his cell phone. “I’m a lot better working with a tire iron than I am with high school math.”
“While you’re doing that, I’m going back to the lab. There’s something about the results we’ve been getting that just doesn’t add up.”
When Grissom walked into the ballistics comparison lab, he saw Catherine and Bobby Dawson—both garbed in white lab coats—hunched over a pair of comparison microscopes mounted a few feet apart on a low lab bench. The rest of the bench surface was covered with rows of marked envelopes and vials, and their individual notepads.
“Do I dare ask how things are going?” Grissom probed.
“Did you come in here to help?” Catherine asked, her eyes staying fixed to the eyepieces of the expensive scope.
“No, not really,” Grissom admitted.
“In that case, things are going painfully slow,” Catherine said with a sigh as she continued to adjust the three-dimensional position of the bullet mounted on the left ocular stage of the microscope.
“I wanted to ask both of you something,” Grissom said, perfectly comfortable with the fact that he was being visually ignored. “Did either of you swab the pistol we found in the truck for GSRs?”
“I didn’t,” Catherine said.
“Me neither,” Bobby echoed.
“So that means David probably took the swabs,” Grissom concluded, sounding not exactly pleased by the revelation.
“Is that a problem?” Catherine asked, finally turning away from the scope to stare curiously at Grissom.
“I’m not sure,” Grissom replied. “He came into my office when I was talking with Brass and Fairfax, and proceeded to tell all of us that he’d confirmed the subject in the truck had fired a weapon just before being shot, based on the interaction of blood droplets with cooling GSRs.”
“Sounds like an impressive piece of work,” Catherine said.
“That’s what I thought too.” Grissom nodded. “But then he went on to say that he’d identified unburned grains of gunpowder from the subject’s hands as being visually and chemically identical to unburned grains found on the Smith & Wesson hammerless pistol in the truck. So now Fairfax is convinced that we’ve exonerated his buy-bust team.”
“Kinda jumping the gun a bit, isn’t he?” Bobby asked.
“Who, Fairfax?”
“Well, yeah, him too; but I’m talking about David. ‘Visually identical’ doesn’t mean a whole lot when you consider that most of the smokeless gun-powders in the world are made up of only a half-dozen possible kernel shapes. And ‘chemically identical’ doesn’t necessarily mean much either, depending on how far he went with his analysis. Hell, you could say the same thing about a couple of Twinkies—they might be visually and chemically ‘identical,’ but that doesn’t mean they came from the same bakery, or even the same state, much less the same package.”
“So you’re saying he had to be talking about class—as opposed to individual—characteristics?” Grissom asked, clearly seeking confirmation for something he’d already suspected.
“Unless you guys have got some fancy new gunpowder analysis instrument I don’t know about,” Bobby replied.
Grissom closed his eyes and sighed.
Wendy Simms looked up from the gas chromatograph/mass spectrogram when Grissom entered the analytical chemistry lab.
“How are you coming with those swabs?” Grissom asked.
Wendy checked her notebook.
“I’ve got results on thirty of the swabs so far, which is less than half of the samples that Catherine collected; but I placed them into the auto-sampler in a random order, thinking that might give us a general location in or on the truck to focus on.”
“And?”
“Nada,” Wendy replied. “And I’ve got the detector ratcheted up to three times normal sensitivity. If there was ever so much as a bindle of cocaine in that truck—much less several kilos—I ought to be seeing something in the way of trace evidence…but I’m not.”
“But then again, it’s always difficult to prove a negative.”
The unmistakable voice of David Hodges. Grissom and Wendy both looked up as the lab tech came into the room.
“What can I say?” David went on as he walked over to the X-ray fluorescence instrument. “It’s not every day that one of us techs gets to solve a puzzle that has the entire graveyard CSI team stymied.”
“No, it isn’t,” Grissom agreed, staring thoughtfully at Hodges. “And that’s exactly why I stopped by. I wanted to take a look at your photo documentation. That GSR–blood droplet interaction might be worth publishing…and maybe even presenting at the next Academy meeting.”
“Do you really think so?” In spite of his thin stature, David managed to look as if his chest was about to explode out of his lab coat.
“Very possibly; let’s take a look.”
David hurried over to his computer and quickly sat down at the keyboard. Moments later, a 50,000x scanning electron microscope image of a still-solidifying GSR particle—looking like a drab and slightly flattened pumpkin at the edge where it had apparently been hit by a microscopic spray of blood—appeared on the flat screen.
“What do you think?” David asked, moving out of the way so that Grissom could get an unimpeded view of the telltale image.
“Very impressive, indeed,” Grissom said. “Have you proven that the impact material is, in fact, blood?”
“Well, actually, no…not yet,” David hedged uneasily. “It seemed pretty obvious that—”
“You’ll want to make that confirmation before you write that paper…and certainly before you write your report,” Grissom said firmly. “Now, what about that unburned gunpowder you found on the pistol and the truck driver’s hands?”
“Oh, uh, yes…of course.” Visibly flustered, David quickly tapped the keyboard again. Moments later, a pair of 20x-magnified images of what looked like identically thick, short, and partially melted segments of black licorice appeared on the screen. “There they are,” he said. “The grains on the left came from the p
istol, and the ones on the right are from the subject’s right hand.”
“Actually, what you have there are unburnedgranules of smokeless gunpowder,” Bobby corrected from the doorway; “or, to put it in more technical terms, unburned extruded tubular kernels.”
“Grains, granules, kernels—what’s the difference?” David asked uneasily as he and Wendy and Grissom watched Bobby walk over to a nearby lab bench, sit down in front of a 20-40x dissection microscope, pull a vial out of his pocket, and pour something into a small plastic tray. He slid the tray underneath the lens of the low-powered scope, made a quick focusing adjustment, then pointed to the adjacent flat-screen monitor.
“That’s the difference,” Bobby said calmly, as he stepped away from the lab bench, allowing David, Wendy, and Grissom to gather around the screen curiously.
“I don’t understand,” David said, looking perplexed.
“Yes, exactly,” Bobby agreed. “What you are looking at on this screen are some of the cut roundflakes of smokeless gunpowder that I just pulled out of one of the live thirty-eight-special cartridges taken from the Smith & Wesson that Gil and Catherine found in the subject’s truck.”
“But those…granules…aren’t even close to—” David started to say.
“No, they’re not. ‘Cut round flakes’ are fast-burning granules of smokeless gunpowder that you would typically find in pistol ammunition; whereas ‘extruded tubular kernels’ are slower burning granules”—Bobby walked over to David’s computer screen—“that are typically found in rifle ammunition.”
“But how can that be—?” David protested. “I—”
“I’m guessing you swabbed the outside of the pistol, probably somewhere near the grip…correct?”
“Yes, of course; that’s what the protocol says to do.”
“It does say that,” Bobby went on. “But it also says to swabboth sides of the weaponseparately, and the inside of the barrel and chamber as well.Had you done that, you would have probably found unburnedflakes of smokeless gunpowder that do not match the swabs from the subject’s hands.”