“Not with certainty,” says DeShield. “But from the depth of the scratches, one in particular under magnification, I would say it is a possibility.”
The judge waffles his wrist, like close call. “I’ll overrule it,” he says.
The problem for the prosecution is that if the jewelry came off, Stobel has not found it.
We turn to DeShield’s analysis of the metal traces, what he collected from the edge of the coffee table, and get into the technical stuff. The question here is whether the metal scraped off the table can be matched to a specific piece of jewelry.
DeShield tells me this is possible.
“Is this like comparing fingerprints?” I ask.
He considers for a moment, then says, “Not usually. We can show the existence or nonexistence of class characteristics in terms of the metal’s chemical composition. This is more likely to allow us to exclude certain possibilities as a potential match.”
He does concede, however, that there are cases in which the presence of what are called “trace elements,” impurities in the metal, can form invisible markers.
“Depending on how rare these are, their percentage to the total composition of the metal, and the number of these impurities, you could have a situation in which there are significant points of comparison in which a positive identification would be possible.”
He is now talking about evidence beyond a reasonable doubt. Find the owner of the jewelry, find the killer.
“Like fingerprints?” I ask.
“There have been cases involving matches of paint,” says DeShield, “in which known and questioned samples have been matched to a certainty of less than one chance in ten billion. This is a higher probability than human fingerprints. This was based on multiple impurities in the paint and the lack of likelihood that the same combination and percentage of these impurities would be replicated in another paint batch.”
“And the same might be true of metals?”
“It’s possible.”
The look on Kline’s face at this moment is ominous. For a moment I think he suspects we have actually found the item of jewelry, a positive match, and that it does not belong to my client. There’s a furious discussion at the counsel table between Stobel and Kline. The detective is shaking his head, like this is not the way the cops read the evidence. Nonetheless, it presents an interesting alternative for the jury.
“Did you have an opportunity to analyze the trace portions of metal removed from the table?”
“I did.”
“And how was this analysis performed?”
“Actually, I used two methods: standard spectrography and an examination under a scanning electron microscope with an energy-dispersive X-ray detector, a process known as EDX.”
This is the stuff that is deadly. I notice that in the jury box eyes are beginning to glaze over. Talk of science.
“What is spectrography?” I ask. “Very briefly.”
“A small portion of the evidence, usually a fraction of a gram, is burned at high temperature. The atomic structure of the substance is disturbed by the heat. In turn, this emits waves of energy, which we observe as colors. These color patterns are focused on a photographic plate and can be read as possessing certain wavelengths which correspond with the precise chemical composition of the substance. It’s a very old process, but reliable.”
He covers the so-called EDX process in similar shorthand fashion. A lot of yawning from the box.
“So you can tell precisely how much iron or copper, or magnesium, so-called impurities, are contained in a sample of metal?”
“That’s right. In theory you take the scrapings from the table, another scraping from a piece of jewelry, and compare them for chemical composition, and in particular the existence of known impurities, trace elements, in known quantities. If there’s enough of them, and they match, voilà.”
“And you can do this with minute amounts of metal?”
“We can. In fact we did not use all of the scrapings we took from the table.”
“You still have more of that sample?”
“We do.”
“So you could turn it over to the police if they needed to do their own tests?”
“We could,” he says, “but there’s no need. They took their own scrapings from the same area.”
This is the point I wish to make; that the cops took their own evidence and have buried it.
“Do you know whether they analyzed the portion they took?”
“Objection,” says Kline. “Hearsay.”
“I’m asking if the witness knows from personal experience,” I tell Radovich.
“Do you know?” says the judge.
“Yes,” says DeShield. “I was present for part of the testing.”
“Overruled,” says Radovich.
“They did tests on the defendant’s jewelry,” says DeShield.
“All of it?”
“To my knowledge, yes.”
“Let’s come back to that later,” I say. “First, can you tell us what you discovered as a result of your analysis?”
“It would be my opinion that whatever made those scratches on the table and left traces of its own metal was custom-made and very expensive,” says the witness.
“And what is that opinion based on?”
“The chemical composition,” says DeShield. “Very high gold content. Twenty-two karat. Somewhat unique for jewelry. Used mostly in India, where labor costs make design and construction of custom-made items of nominal concern. People buy gold there for its intrinsic value. A hedge against inflation,” he says.
“Is that your opinion as to the source of this jewelry?”
“Most likely. Very little is imported for sale here. Too expensive,” says DeShield.
“Did you find markers? Any impurities in the metal?”
“No. It’s the problem with gold of that quality,” he says. “Trace elements-lead, iron, magnesium-these normally will have leached out long ago.”
There’s the semblance of a smile from Stobel, and a knowing glance from Kline, who actually slaps the table in relief, though he tries to conceal this as merely stretching when he realizes he has drawn attention.
“So there is no way chemically to determine a positive identification between the trace metal and an item of jewelry?”
“Not chemically. No.”
“Is there another way?”
“In my opinion, it is possible.”
The smile melts on Kline’s face.
“How?”
“Tool marks,” says the witness.
DeShield had come to me with this a week ago. While he could not match the metals because of their purity, there is another common characteristic of gold. It is malleable, soft, especially in the twenty-two-karat variety he has identified here. He now explains this to the jury.
“The fact is that the underside of that table contains small ridges, raised areas that are part of its design. These are unique in their size and spacing.”
He has a picture to illustrate this, and we place it on the easel, a ten-power magnification that makes these grooves look like the mountains of the moon or, more accurately, according to DeShield, the teeth on a key.
“Find gold jewelry with gouges that match those grooves, and you would have positive identification.”
I allow this to seep in at Kline’s table, like sludge in beach sand, while I plow through our box of evidence. With the rustle of paper, he is all eyes. For a moment he gets out of his chair, looks at Stobel.
“Your Honor, could we approach?”
“Not now,” says Radovich.
Kline would like to break a dramatic moment. He can’t be sure, but there is a chance we have the missing object, the item of gold. How, he cannot know.
I pull out a paper sack, sealed with an evidence tag. All of these items have been collected by us under the watchful eye and direction of the special master, appointed by the court to ensure that there are no chain-of-custody problems, allegations of hanky-panky with the physical evidence. They have been examined and sealed in evidence bags by the special master and turned over to the court.
“Mr. DeShield, I’m going to show you a bag and ask you if you can identify its contents.”