"No. Again, because local law enforcement authorities don't believe these deaths were murder, there's a problem of access to the bodies."

"What about the medical records of the alleged victims?"

"I managed to get the records of two victims from angry family members. But experts have been over both of them in microscopic detail, and they haven't turned up anything suspicious."

Chris blinked against stinging sweat that the rain had washed into his eyes.

"But I'm told that radiation could explain the variation in the cancers," Morse went on. "You expose somebody to radiation, there's no way to predict how their cells will react."

Chris nodded, but something about this idea bothered him. "Your expert is right. But then, why are blood cancers the only result? Why no solid tumors? Why no melanomas? And why only superaggressive blood cancers? You couldn't predict something like that with radiation."

"Maybe you could," Morse suggested. "If you were a radiation oncologist."

"Maybe," Chris conceded. "If you managed to expose the bone marrow primarily, you might get more blood cancers than other types. But if that's true, you just shrank your suspect pool by about ten thousand people."

Morse smiled. "Believe me, every radiation oncologist in Mississippi is under investigation at this moment."

"How many are there?"

"Nineteen. But it's not a simple matter of alibis. I can't ask some doctor where he was on a given day at a given time, because we have no way to know when the victims were dosed. You see?"

"Yeah. Dragnet methods are out the window. But it's not just a doctor you're looking for, right? It's the lawyer, too. If you're right, he functions almost like the killer's agent."

"Exactly. Only he handles an assassin instead of a quarterback or a singer."

Chris laughed softly. "How would a relationship like that get started? You can't go scouting for promising young assassins. There's no national draft. Does your greedy lawyer put an ad on the Internet to recruit someone who can kill people without a trace? Does he hire a medical headhunter?"

"I know it sounds ridiculous when you put it like that, but we're talking about a lot of money here."

"How much?"

"Millions in every case. So the lawyer has a pretty big carrot to hold out in front of someone who probably makes a hundred grand or less at his legitimate job."

To break the monotony of the ride, Chris gently steered left and right. Morse gave him room to ride his serpentine course.

"Lawyers get to know a lot of professional criminals in the course of their work," she pointed out. "And necessity is the mother of invention, right? I think this guy simply saw a demand for a service and then found a way to provide it."

Chris pedaled out in front of her so that a large truck could pass. Illegally, since big trucks weren't allowed on the Trace. "A lot of what you say makes sense," he called over the sound of the receding truck, "but I still say your theory doesn't add up."

"Why not?" Morse asked, pulling alongside again.

"The time factor. If I want to kill someone, it's because I really hate them, or because I stand to gain a hell of a lot if they die. Or maybe I stand to lose millions of dollars if my wife goes on living, like you said yesterday. What if she wants to take my children away forever? I'm not going to wait months or years for her to croak. I want immediate action."

"Even if that's the case," said Morse, "the most likely result of any conventional murder-especially in a divorce situation-is the killer going to jail. And if you're not going to try the murder yourself, who do you hire? You're a multimillionaire. You don't have a gangsta posse to turn to. Imagine how someone that desperate might react to a slick lawyer offering him a risk-free road out of his problems. A perfect murder is worth waiting for."

She has a point, Chris thought. "I can see that. But no matter how you slice it, there's an element of urgency in a divorce situation. People go crazy. They'll do anything to get out of their marriage. There's a frantic desire to move on, to marry their lover, whatever."

"You're right, of course," Morse agreed. "But you've already waited years for your freedom. Maybe decades. Any divorce lawyer can tell you that obtaining a divorce-the whole process from beginning to end-can take a very long time. If the divorce is contested, we're talking nightmare delays. Even filing under irreconcilable differences, spouses often argue back and forth for a year or more. People are hurting, they stonewall, negotiations break down. You can wind up in court even if it's the last thing you wanted. Years can go by." Morse was suddenly puffing hard. "If your lawyer told you that in the same amount of time that your divorce would take, he could save you millions of dollars, guarantee you full custody of your children, and prevent them from hating you-you'd have to at least consider what he had to say, wouldn't you?"

They were crossing the high bridge over Cole's Creek. Chris braked to a stop, climbed off, and leaned the Trek against the concrete rail.

"You've got me," he said. "If you remove urgency from the equation, then a delayed-action weapon becomes viable. You could use something like cancer as a weapon. If it's technically possible."

"Thank you," Alex said softly. She leaned her bike against the concrete and gazed at the brown water drifting lazily over the sand fifty feet below.

Chris watched a burst of tiny drops pepper the surface of the water, then vanish. The rain was slacking off. "Didn't you tell me that some of the victims were men?"

"Yes. In two cases, the surviving spouses were female."

"So there's a precedent for women murdering the husbands in this thing."

Morse took a deep breath, then looked up at him and said, "That's why I'm here with you, Doctor."

Chris tried to imagine Thora secretly driving up to Jackson for a clandestine meeting with a divorce lawyer. He simply couldn't do it. "I buy your logic, okay? But in my case it's irrelevant, and for lots of reasons. The main one is that if Thora asked me for a divorce, I'd give her one. Simple as that. And I think she knows that."

Morse shrugged. "I don't know the lady."

"You're right. You don't." The concrete rail was not even waist high to Chris. He sometimes urinated off it during his rides. He suppressed the urge to do so now.

"It's beautiful down there," Morse said, gazing down the winding course of the creek. "It's looks like virgin wilderness."

"It's as close as you'll find. It hasn't been logged since the 1930s, and it's federal land. I spent a lot of time walking that creek as a boy. I found dozens of arrowheads and spear points in it. The Natchez Indians hunted along that creek for a thousand years before the French came."

She smiled. "You're lucky to have had a childhood like that."

Chris knew she was right. "We only lived in Natchez for a few years-IP moved my dad around a lot, between mills, you know?-but Dad showed me a lot of things out in these woods. After heavy rains, we'd each take one bank of the creek and work our way along it. After one mudslide, I found three huge bones. They turned out to be from a woolly mammoth. Fifteen thousand years old."

"Wow. I had no idea that kind of stuff was around here."

Chris nodded. "We're walking in footsteps everywhere we go."

"The footsteps of the dead."

He looked up at the sound of an approaching engine. It was a park ranger's cruiser. He lifted his hand, recalling a female ranger who'd patrolled this stretch of the Trace for a couple of years. After she moved on, he'd seen her face on the back of a bestselling mystery novel set on the Trace. The place seemed to touch everyone who spent time here.

"What are you thinking, Doctor?"