He tells me where he is, which electron microscope, and I grab my lab coat off the back of my desk chair, hurrying out the door. I decide to avoid the elevator. Not only is it notoriously slow in my state-of-the-art biotech headquarters but I intend to duck and dodge the FBI every chance I get. A good way to start is by using the emergency stairs. While anyone can take them to exit the building, you can’t access our floors without an ID badge or a code.

So I’m not likely to run into anyone, and my clogs echo on the metal-edged concrete steps as I descend to the lower level. It’s as quiet as a bomb shelter in the stairwell as I go down and down, unlocking the door at the bottom. It opens into our evidence bay, where we process large items, typically cars and trucks, but we’ve also recovered evidence from supercars, motorcycles, Jet Skis, and even a homebuilt hang glider that obviously didn’t work very well or it and its owner wouldn’t have ended up here.

The lights are on a low, energy-saving setting, and I briskly walk through the gloom, passing exam spaces occupied by current cases. A boat under a tent will be fumed with superglue to develop possible latent prints, and two spaces down from that is the camper where a suspected murder-suicide occurred. Next to that, a stand-alone bay is covered in blood-spattered-and-streaked white paper from ceiling to floor to reconstruct a stabbing.

I head toward an illuminated red IN USE sign above the concrete bunker housing the transmission electron microscope, the TEM. Scanning my thumbprint on the biometric reader, I pass through the stainless-steel door as it slides open with a swoosh that always reminds me of Star Trek. I’m greeted by the familiar rush of positive-pressure air blowing my hair as I step inside, and the door whispers shut behind me.

“Howdy. Come on in and take a load off,” Ernie says in the near dark from the console of the half-ton microscope. “Because you’re going to want to sit down for this.”

My top trace-evidence examiner always reminds me of a submarine pilot as he sits in front of a periscope-like thick metal tube that rises nearly to the ceiling and is topped by the assembly of the cathode, what most people call an electron gun but I tend to think of as more like a lightbulb. Its simple hairpin-shaped tungsten wire fires thermo-ionic emissions at whatever we decide to analyze, and I always find it cavelike in here, stuffy and claustrophobic.