attractive copper

"Not sure yet. Hang on." I walked over to the wall and held up my hand about half an inch from its surface. I closed my eyes and focused on a very faint trace of energy left there. After several moments of concentration, I lowered my hand again. "There's something there," I said. "But it's too faint for me to make it out without using my Sight. And I'm getting sick of doing that."
"What does that mean?" Murphy asked me.
"It means I need something from my kit. Be right back." I went outside and down to my car, where I kept a fisherman's tackle box. I snagged it and went back up to the dead woman's bedroom.
"That's new," Murphy said.
I set the box on the floor and opened it. "I've been teaching my apprentice thaumaturgy. We have to go out to the country sometimes, for safety's sake." I rummaged through the box and finally drew out a plastic test tube full of metallic grains. "I just tossed things into a grocery sack for the first couple of weeks, but it was easier to put together a more permanent mobile kit."
"What's that?" Murphy asked.
"Copper filings," I said. "They conduct energy. If there's some kind of pattern here, I might be able to make it out."
"Ah. You're dusting for prints," Murphy said.
"Pretty much, yeah." I pulled a lump of chalk out of my duster's pocket and squatted to draw a very faint circle on the carpet. I willed it closed as I completed the circle, and felt it spring to life, an invisible screen of power that kept random energies away from me and focused my own magic. The spell was a delicate one, for me anyway, and trying to use it without a circle would have been like trying to light a match in a hurricane.
I closed my eyes, concentrating, and poured an ounce or two of copper filings into my right palm. I willed a whisper of energy down into the filings, enough to create a magical charge in them that would draw them toward the faint energy on the wall. When they were ready, I murmured, "Illumina magnus." Then I broke the circle with my foot, releasing the spell, and cast the filings outward.
They glittered with little blue-white sparks, crackling audibly as they struck the wall and stayed there. The scent of ozone filled the air.
I leaned forward and blew gently over the wall, clearing any stray filings that might have clung to the wall on their own. Then I stepped back.
The copper filings had fallen into definite shapes - specifically, letters:
EXODUS 22:18.
Murphy furrowed her brow and stared at it. "A Bible verse?"
"Yeah."
"I don't know that one," she said. "Do you?"
I nodded. "It's one that stuck in my head: 'Suffer not a witch to live.'"


White Night, Chapter 1, Page 6-8