Chan took the cap off the small metal evidence button and with tweezers removed a layer of snowy cotton, revealing the two tiny bright turnings. She pushed back her roller chair to a counter behind her and proceeded to place a double-sided adhesive square of black carbon tape on a tiny aluminum stub. On this she mounted the shaving that seemed to have the most surface area. It was maybe half the size of a normal eyelash. She turned on a stereo-optical microscope, positioned the sample on the stage, and adjusted the light wand to take a look at a lower magnification before she resorted to the SEM.

“I’m seeing two different surfaces,” she said as she adjusted the focus. “One real shiny, the other sort of dull gray.”

“That’s different from the Warrenton sample,” I said. “Both surfaces were shiny, right?”

“Correct. My guess would be that one of the surfaces here was exposed to atmospheric oxidation. For whatever reason that might be.”

“Do you mind?” I asked.

She scooted out of the way and I peered through the lenses. At a magnification of four, the metal turning looked like a ribbon of crumpled foil, and I could just barely make out the fine striations left by whatever had been used to shave the metal. Mary took several Polaroid photographs and then rolled her chair back to the SEM console. She pushed a button to vent the chamber, or release the vacuum.

“This will take a few minutes,” she said to us. “You can wait here or go and come back.”

“I’m getting coffee,” said Marino, who had never been a fan of sophisticated technology and most likely wanted to smoke.

Chan opened a valve to fill the chamber with nitrogen to keep contamination, such as moisture, out. Next she pushed a button on the console and placed our sample on an electron optics table.

“Now we got to get it to ten to the minus six millimeters of mercury. That’s the vacuum level needed to turn on the beam. Usually takes two or three minutes. But I like to pump it down a little more than that to get a really good vacuum,” she explained, reaching for her coffee. “I think the news accounts are very confusing,” she then said. “A lot of innuendo.”

“So what else is new?” I wryly commented.