As his tires thrummed along the pavement's edge, he saw another biker in the distance, approaching on the opposite side of the Trace. As the distance closed, Chris saw that the rider was female. He raised his hand in greeting, then hit his brakes.

The rider was Alexandra Morse.

Agent Morse wasn't wearing a biking helmet, but her dark hair was drawn back into a soaking-wet ponytail, making her facial scars all the more prominent. It was the scars that allowed Chris to recognize her. He could hardly believe her presence, and he was about ready to sprint right past her when she crossed the road and hissed to a stop a yard away from him.

"Good morning, Doctor."

"What the hell are you doing?" he asked.

"I needed to talk to you. This seemed like a good way to do it."

"How did you know I was here?"

Morse only smiled.

Chris looked her from head to toe, taking in the soaked clothes stuck to her body and her dripping ponytail. She had chill bumps on her arms and legs, and the cotton TULANE LAW shirt she was wearing would take forever to dry, even if the rain stopped.

"And the bike?" he asked. "You a big cyclist?"

"No. I bought it four days ago, when I found out that you were a biker and your wife was a runner."

"You've been following Thora, too?"

Morse's smile faded. "I've shadowed a couple of her runs. She's fast."

"Jesus." Chris shook his head and started to ride away.

"Wait!" Morse cried. "I'm not a threat, Dr. Shepard!"

He stopped and looked back. "I'm not so sure of that."

"Why not?"

He thought of Darryl Foster's words. "Call it instinct."

"You have good instincts about sources of danger?"

"In the past I have."

"Even when those sources are human?"

A red pickup truck whizzed past, its rider staring at them.

"Why don't we keep riding?" Morse suggested. "We'll be less noticeable talking that way."

"I don't intend to continue yesterday's conversation."

She looked incredulous. "Surely you must have some questions for me."

Chris looked off into the trees, then turned and let some of his anger through his eyes. "Yes, I do. My first question is, did you personally see my wife go into this divorce lawyer's office?"

Morse took a small step backward. "Not personally, no, but-"

"Who did?"

"Another agent."

"How did he identify Thora?"

"He followed her down to her car, then took down her license plate."

"Her license plate. No chance of a mistake? No chance he got one number wrong, and it could have been someone else?"

Morse shook her head. "He shot a picture of her."

"Do you have that picture?"

"Not on me. But she was wearing a very distinctive outfit. A black silk dress with a white scarf and an Audrey Hepburn hat. Not many women can pull that kind of thing off anymore."

Chris gritted his teeth. Thora had worn that same outfit to a party only a month ago. "Do you have any recordings of her conversation with the lawyer? Copies of any memos or files? Anything that proves what they talked about?"

Morse reluctantly shook her head.

"So you admit that it's possible that they talked about wills and estates, or investments, or something else legitimate."

Agent Morse looked down at her wet shoes. After a while, she looked back up and said, "It's possible, yes."

"But you don't believe it."

She bit her bottom lip but said nothing.

"Agent Morse, I happen to know from my wife's recent behavior that what you suggested yesterday is impossible."

The FBI agent looked intrigued, but instead of asking what he was talking about, she said, "It's ten miles back to your truck. Why don't we ride back together? I promise not to piss you off, if I can help it."

Chris knew he could leave Morse behind in seconds. But for some reason-maybe just the manners he'd been raised with-he decided not to. He shrugged, climbed into his pedal clips, and started southward at an easy pace. Morse fell in beside him and immediately started talking.

"Have you called anybody about me?"

He decided to leave Darryl Foster out of the conversation. "I figured you'd already know the answer to that. Aren't you tapping my phones?"

She ignored this. "I'm sure you have some questions for me, after all I said yesterday."

Chris shook the rain out of his eyes. "I'll admit I've done some thinking about what you told me, especially about the medical side."

"Good. Go on."

"I want to know more about these unexplained deaths, as you called them."

"What do you want to know?"

"How the people died. Was it a stroke in every case?"

"No. Only my sister's."

"Really. What were the other causes of death?"

"Pulmonary embolism in one. Myocardial infarction in another."

"What else?"

A hundred feet of road passed beneath them before Morse answered. "The rest were cancer."

Chris looked sharply over at her, but Morse kept watching the road. "Cancer?"

She nodded over her handlebars, and water dripped off her nose. "Fatal malignancies."

"You're kidding, right?"

"No."

"You're telling me this cluster of suspicious deaths that has you so worked up involves people who've died of cancer?"

"Yes."

He thought about this for a while. "How many victims were there? Total?"

"Nine deaths tied to the divorce lawyer I told you about. Six cancers that I've traced so far."

"Same kind of tumor in every person?"

"That depends on how picky you are. They were all blood cancers."

"Call me picky. Blood cancer encompasses a whole constellation of diseases, Agent Morse. There are over thirty different types of non-Hodgkin's lymphomas alone. At least a dozen different leukemias. Were all the deaths from one type of blood cancer, at least?"

"No. Three leukemias, two lymphomas, one multiple myeloma."

Chris shook his head. "You're out of your mind. You really believe someone is murdering people by giving them different kinds of cancer?"

Morse looked over at him, and her eyes were as grim as any he'd ever seen.

"I know it."

"That's impossible."

"Are you so sure? You're not an oncologist."

Chris snorted. "It doesn't take an oncologist to realize that would be a stupid way to murder someone-even if it were possible. Even if you could somehow induce cancer in your victim, it could take years for that person to die, if they died at all. A lot of people survive leukemia now. Lymphomas, too. And people live well over five years with myeloma after bone marrow transplants. Some patients have two transplants and live ten years or more."

"All these patients died in eighteen months or less."

This brought him up short. "Eighteen months from diagnosis to death? All of them?"

"All but one. The myeloma patient lived twenty-three months after an autologous bone marrow transplant."

"Aggressive cancers, then. Very aggressive."

"Obviously."

Morse wanted him to work this out for himself. "These people who died…they were all married to wealthy people?"

"All of them. To very wealthy people."

"And all the surviving spouses were clients of the same divorce lawyer?"

Morse shook her head. "I never said that. I said all the surviving spouses wound up in business with the same divorce lawyer-and only after the deaths of their spouses. Big deals, mostly, one-offs that had nothing to do with the lawyer's area of expertise."

Chris nodded, but his mind was still on Morse's cancer theory. "I don't want to get into a technical argument, but even if all these patients died from leukemias, you're talking about several different disease etiologies. And the actual carcinogenesis isn't understood in a majority of types. Include the lymphomas, and you're dealing with entirely different cell groups-the erythroid and B-cell malignancies-and the causes of those cancers are also unknown. The fact that your 'blood cancers' killed in less than eighteen months is probably their only similarity. In every other way they're probably as different from each other as pancreatic cancer and a sarcoma. And if the best oncologists in the world don't know what causes those cancers, who do you think could intentionally cause them to commit murder?"