“How old are these skeletons?” Nick asked. “Did they find anything that could give us a postmortem interval?”

She looked. “They tested the bones for nitrogen levels; their best estimate is between twenty and fifty years.”

“Can’t they narrow it down any more than that?” Danny asked.

“The older the body, the harder it is to tell,” Kegan said. “Once the soft tissues are gone and the body is fully skeletonized, age becomes very difficult to estimate.”

“Twenty to fifty years—that doesn’t give us much to go on.”

“It tells us something important,” Nick said. “All four bodies are in the same age range; that means one killer could be responsible for all four, and he could still be alive.”

“All three,” Kegan corrected.

“Excuse me?”

“The fourth skeleton—one of the two we found just the other day— it’s two hundred years old.”

“What?” Nick took the report from her hand and looked at it.

“The cause of death was the same—a blow to the back of the head— but the condition of the skeleton was different. On the first three bodies there were still shreds of fabric surrounding the bone. They were synthetic fibers—synthetics break down a lot more slowly than natural fibers like cotton or silk, and none of them existed before the early twentieth century. On the fourth body there were no fibers at all, and that suggests greater age. There were artifacts that helped date the fourth body as well: four buttons made of ivory—they were commonly used in the eighteenth century but rarely since. There were also fragments of brass near the feet.”

“Shoe buckles?” Nick suggested.

“That’s what they think at Quantico. Low nitrogen levels, absence of synthetic fibers, and datable artifacts—it all adds up to two hundred years, more or less.”

“Then we’ve got two different killers here,” Danny said, “a historical one and one that might still be alive.”

“And we’re not finished excavating yet,” Kegan said. “Who knows what else we might find.”

“What’s taking so long?”

“It’s a slow process, Danny. The soil above every grave could contain forensic evidence—we have to go through it one shovelful at a time. We’re excavating, not gardening. It could take a few more days still.”

“Somebody knows about this graveyard,” Nick said almost to himself.

“Well, obviously.”

“I mean they not only know its location—they know what it was used for two hundred years ago. Who would know that?”

No one had an answer.

“Could the victims be connected in some way—the old one and the new ones?”

“We’re still waiting on mitochondrial DNA results,” Kegan said. “That might tell us if any of them were related—at least if they shared a common female ancestor.”

“Let me know as soon as you get them,” Danny said. “Is there anything else?”

Kegan flipped through the reports. “Nothing out of the ordinary.”