I gave her the number of the fax machine in my office, and I did not let her know my irritation. But I did give her a hint.

“Mary, in the future, it’s best if you let me know about my cases before you start sending lab results to others,” I calmly said.

“I’m sorry,” and I could tell she very much was. “The investigator called at five as I was halfway out the door.”

The reports were in my hands two minutes later, and McGovern opened her battered briefcase to retrieve her copies. She watched me as I read. The first was an analysis of the metal-like shaving that I had recovered from the dead woman’s cut to the left temporal region. According to the scanning electron microscope and energy dispersive X ray, or SEM/EDX, the elemental composition of the material in question was magnesium.

As for the melted debris recovered from the victim’s hair, those results were just as inexplicable. A FTIR, or Fourier transform infrared spectrophotometer, had caused the fibers to selectively absorb infrared light. The characteristic pattern turned out to be that of the chemical polymer polysiloxane, or silicone.

“A little strange, don’t you think?” McGovern asked me.

“Let’s start with magnesium,” I said. “What comes to mind is sea water. There’s plenty of magnesium in that. Or mining. Or the person was an industrial chemist or worked in a research lab? What about explosives?”

“If potassium chloride came up, then yes. That could be flash powder,” she answered. “Or RDX, lead styphnate, lead azide of mercury fulminate if we’re talking about blasting caps, for example. Or nitric acid, sulfuric acid, glycerin, ammonium nitrate, sodium nitrate. Nitroglycerin, dynamite, and so on and so on. And I will add that Pepper would have picked up on high explosives like that.”

“And magnesium?” I asked.

“Pyrotechnics, or fireworks,” she said. “To produce the brilliant white light. Or flares.” She shrugged. “Although aluminum powder is preferred, because it keeps better, unless the magnesium particles are coated with something like linseed oil.”

“Flares,” I thought out loud. “You light flares, strategically place them, and leave? That could buy you several minutes, at least.”

“With the appropriate fuel load, it could.”

“But that doesn’t explain an unburned turning or shaving of it embedded in her wound, that would appear to have been transferred by the sharp instrument she was cut with.”

“They don’t use magnesium to make knives,” McGovern observed.

“No, nothing like that. It’s too soft. What about the aerospace industry, because it’s so light?”

“Most definitely. But in those instances, there are alloys that would have come up during testing.”

“Right. Let’s move on to silicone, which doesn’t seem to make any sense. Unless she had silicone breast implants before they were banned, which she clearly didn’t.”