In his sterile office, a long table had been added. It was covered with a mountain of white plastic disks. Smoke detectors.
I did a rough count and stopped before one hundred.
“When the track refurbished the barns,” Wertzer sniffed, “they put in new smoke detectors.”
The plastic covers were loose, hanging on their hinges. Wertzer picked one up. I could see the inside mechanisms. Every smoke detector had three parts: a printed circuit board, an electronic horn that resembled a small bicycle bell, and a brass cylinder.
“May I?” I held out my hand.
He handed me the detector. I touched the brass cylinder.
“That’s the ionization chamber,” he said.
“I know.”
The cynicism was back. “You know?”
“When the smoke gets inside the cylinder, it knocks an electron off the oxygen and nitrogen atoms in the air, ionizing them. The negative electron gets attracted to a plate that has a positive charge, and the positive atom heads for the plate with the negative voltage.” I touched the bell. “Then this goes off.”
He stared at me.
“I worked as a forensic geologist. For the FBI. Before I was an agent. Which I’m not anymore.”
He rolled his eyes. “I wish I could run another polygraph.”
“And this time I’d pass it.”
He gave a weary nod, as if to say this last story was so preposterous it was probably true.
I picked up another plastic disk, checking it.
“We dusted them for prints,” he said. “They were clean.”
“All of them?”
He nodded and sniffed.
An idea was ticking at the back of my tired mind. Nobody would wipe down a bunch of smoke detectors unless . . . The batteries. Nine-volt batteries. There were hundreds of nine-volts powering that tube under the starting gate. I lifted the plastic cover.
“Oh rats,” I muttered.
“What’s the matter?” he asked.
I opened another disk. And another. All the nine-volt batteries were snapped into their cap buckles. The red and black wires snaked to the circuit board.
“Were any batteries missing?” I asked, just in case.
“Not that I saw.”
“And why was the track getting rid of these?”
“They were too sensitive.”
I looked at him. “I was in that barn fire. Sensitive smoke detectors are a good thing.”
“Sure. For smoke. But that heavy stink in those barns? It tripped up the really good detectors. They can’t tell the difference between smoke, hay, dust. All of it interrupts the electrical current. One horse with bad gas could set off the whole barn.”
I looked down at the disk in my hand. The only thing that looked different from a standard smoke detector was the ionization chamber. It was dented, only that didn’t seem like something done by the manufacturer. I picked up another disk. Its chamber was dented too, and scraped at the bottom. Pried open.
“By the way,” he said, “I found all of these piled up near your aunt’s barn.”
“Really,” I said. Dogged. The man refused to give up. He was still testing my story. “She’s not my aunt. And again, for the record, I had nothing to do with lighting that fire.”
He sighed and blew his nose.
I lifted the chamber’s metal cap, and suddenly that tickling idea ran down my spine. The upper ionizing plate was undamaged, but the lower plate caught my attention. It was wobbling, wrenched off its base. Although batteries provided voltage, most detectors’ ionization chambers were run by a different power source. Alpha particles. When I was in the FBI lab, the smoke detectors often wound up in mineralogy for forensics. Radioactive minerals provided the alpha particles. And most manufacturers used Americum 241. A thin layer was deposited on a piece of foil that was encased inside the metal shield to prevent any radiation leakage. One detector usually contained one microcurie of radiation, which the brass casing could easily block. The danger came when the ionization chamber was breached or disturbed.
When airborne, Americum 241 was deadly.
I yanked off the lower plate.
“Hey!” Wertzer said. “What are you doing?”
“It’s gone.”
“What?”
“The alpha emitter.” I pointed to where the foil should be. “The ionizing strip. It’s gone.”
“So?”
I picked up another detector. “Are all the bottom plates loose?”
He grabbed one, checking for himself.
“You handled these?” I asked.
“Why?”
Because I was looking at his watering eyes. The red nose. The way he leaned against the table, as though standing required too much effort. His “cold” could be a sign of a weakened immune system. “Who else touched these?”
“Two guys from the station. They helped me load the truck.”
“Where are they?”
He hesitated. “Out. Sick.”
I placed the disk on the table and backed away. “All three of you need to get to the hospital. Have them test you for radiation exposure. And call a HazMat team. Get these to the state lab.” I looked around for something to wipe my hands on. “Tell the doctors you were exposed to Americum 241. The half-life isn’t short.”
“How long?”
Plutonium and radon were more well known, but Americum 241 had a half-life that was lodged in my memory because of its clean arithmetic. Roughly double its name. “Five hundred years,” I said.
Wertzer stared at me for a long moment. Then he said, “I almost wish you were lying again.”