“But I can’t just walk out with you. There are cameras all over the place, especially around the entrance. You’ll have to help me.”

“How?”

“I need to use your cell phone.”

She takes a silver Motorola from her pocket and hands it to me. Before she can change her mind, I dial Michael Wells’s cell phone. For a few moments I think he’s not going to answer, but then he does.

“It’s Cat.”

“Christ, it’s about time. Are you all right?”

“Yes and no. My aunt is dead, and things are very crazy right now. I’m in New Orleans, and I need to get back to Natchez. The police aren’t looking for me now, but they will be soon. Would it be completely shameless of me to ask you for help again?”

Michael takes a moment to process all this. “Where in New Orleans are you?”

“FBI headquarters.”

“Where’s that?”

“By the University of New Orleans.”

“UNO is by Lakefront Airport.”

“Yes. You can see the airport from the windows here.” Not from the office I’m in, of course, but from the fourth floor.

“If you can get to Lakefront Airport, I can fly down and get you.”

My pulse rate kicks up. “Are you serious?”

“Sure. I’ve flown in there a dozen times. Last time I watched the Dave Matthews Band at UNO.”

“Michaelare you sure you can get away?”

“What will the police do if they find you?”

“Put me in jail.”

“On what charge?”

“Murder.”

“Did you kill anybody?”

“No.”

“Then I can get away. I’ll have to arrange for coverage, though. Call my cell phone in an hour. I should be airborne and on the way by then. We’ll take it from there. If there’s any problem with the phones, just get your ass to Lakefront and start watching the planes come in. I’ll be in a blue and white Cessna 210. Registry number N324MD.”

By the time I walk into the fourth-floor hallway, Hannah Goldman has been gone for ten minutes. She was to say her good-byes to Kaiser, then slowly make her way down to her car in the parking lot.

My job is to get to the FBI’s motor pool without being seen by anyone who knows who I am. Occupying a large part of the building’s basement level, the motor pool has huge garage doors that open into the parking lot. I’ve been down there a couple of times before, when I rolled out with the FBI forensic team on the serial case where I first met Sean.

The elevator is only thirty feet down the hall, and I’m nearly to it when I hear John Kaiser’s voice.

“Cat? Where are you going?”

I turn and give him a little wave. He’s standing by the office I just left, a tall figure who looks more than anything like a concerned father.

“I feel sick. I need to get to the bathroom.”

“Down past the elevator, on the right.” He starts walking toward me. “Did the food come? Did that make you sick?”

Someone did bring up a tray of sandwiches after Hannah left, but I didn’t touch it. “No, I was about to eat it when I got a wave of nausea.”

“That may be from the blow to your head. I was coming to show you this.” Kaiser has almost reached me. He’s holding something in his hand.

“What is it?”

“Early results on those cultures you asked for. The saliva from the bite marks on Quentin Baptiste.”

The dead homicide detectivevictim number six. “Oh, right. What does it show?”

He hands me the lab report. “You tell me.”

I glance over the letters and numbers, trying to pretend that my nerves aren’t shot and that my mind is on the piece of paper in my hand rather than on escaping this building. What I see is a microbiological snapshot of an average human mouth. Except for one thing.

“That’s weird.”

“What?” asks Kaiser.

“Maybe it’s a mistake.”

“What?”

Well, twelve hours is early, but we ought to at least see some Streptococcus mutans growing. You have that particular strep in abundance in any mouth with teeth in it. S. mutans thrives on hard surfaces. It produces the acid that causes cavities.“

“And you don’t have it there?”

“No.”

“Well, if it’s not a mistake, what would that mean?”

“It could mean a couple of things. The saliva may have come from someone taking a course of antibiotics. That would disturb the normal flora of the mouth. I’d look for penicillin, or even more likely, penicillin with gentamicin.” I try to concentrate on the lab report, but all I can keep in my mind is Hannah Goldman waiting for me downstairs.

“Cat?” prompts Kaiser.

“I’m sorry, I was thinking. This saliva could also have come from an edentulous person.”

“What’s that?”

I shrug, thinking the answer self-evident. “Someone without teeth.”

“Somebody who wears dentures?”

“No. Somebody who owns dentures but doesn’t wear them. Dentures have hard surfaces, with cracks and crevices that are ideal for bacterial colonization, just like real teeth. It might be someone who lives alone. Who doesn’t feel the need to put in his teeth, because no one ever sees him.”

Kaiser looks interested. “Would he necessarily have to be old?”

“God, no. Lots of people have teeth so bad they rot out by their thirties. You might look for somebody who needs dentures but can’t afford them.”

“A lot of convicts have their teeth pulled in prison,” Kaiser reflects. “It makes positive identification harder in subsequent trials.”

“Well, maybe this culture will get us somewhere, like I hoped. You can check all the male relatives of the victims for infections, prison records, or for teeth, period. Look, I really need to get to the bathroom.”

“Oh, yeah. Sorry.”

“May I keep this report?”

“Sure.”

I stuff it into my back pocket. “Let’s see what grows out after another six hours.” When I’ll be long gone. I pat Kaiser on the arm, then walk quickly up the hall to the bathroom. As I push open the door, I cut my eyes right.

He’s no longer in the corridor. Backpedaling fast, I dart to the elevator. The fire stairs are tempting, but this is probably one building where if you open a fire door, all hell breaks loose.

Before the elevator door closes, a blonde woman wearing a blue skirt suit hurries in after me and smiles. I smile back and press the button for the basement. I sense her looking at my clothes. They look pretty rough. Definitely not the uniform of female FBI agents.

“Are you okay?” she asks.

“Oh, yes.” I offer my hand. “Catherine Ferry. I’ve been working the NOMURS case as a consultant for John Kaiser. I’m a forensic odontologist.”

She looks impressed and interested. “I heard they found another victim.”

“Yes. A cop this time.”

“Wow.”

The elevator stops on the second floor.

“This is me,” she says. “Good luck.”

The door opens onto a cube farm with men and women walking purposefully between partitions. When the door closes, I breathe a sigh of relief and sag against the wall. In twenty seconds, the elevator opens to the concrete-floored motor pool.

About a dozen government sedans are parked diagonally against a wall on my left. To my right are two big black Suburbans, the SUVs used by the FBI forensic team. Thirty yards across the basement lot are the big overhead doors that can get me out of the building. I don’t see anyone, but there’s bound to be someone here.

Something clangs in the emptiness. The sound of a heavy tool being dropped on concrete. Praying that the careless mechanic is underneath a vehicle, I walk briskly across the lot toward the doors. As I near them, I see a large white button not unlike those beside the doors in ERs and surgical suites. I should have a story ready in case someone asks what I’m doing down here, but I don’t. If someone challenges me, I’ll just have to wing it.

I hit the big button, and an overhead chain drive lifts the big door in front of me with no more fuss than my garage door at home. When it’s four feet off the ground, I duck under it and walk quickly up the ramp to the outdoor parking lot.