“There are two sources of DNA in the body, Danny. You can get it from the nucleus of a cell—that’s nuclear DNA—or you can get it from the mitochondria. Nuclear DNA degrades rapidly—it would be almost impossible to get a good sample from bones this old, so we used mito-chondrial DNA from the teeth. Teeth are almost indestructible—they’re the toughest biological evidence around. The only problem is that you can’t tell as much from mitochondrial DNA.”

“Why not?” Danny asked.

“Because it’s passed directly from mother to child—it lacks the father’s DNA sequence. That means you can’t use it to, say, test for paternity— but since a mother and her children share identical mitochondrial DNA, you can at least use it to tell if two people have a common female ancestor.”

“And what did the tests show?”

“Are you ready for this? All four bodies are consanguine—they have a common lineage.”

“Are we talking brothers or cousins or what?”

“There’s no way to know,” Nick joined in. “All it means is that they share a common female ancestor somewhere in the past—a mother, or a grandmother, or even somebody who lived hundreds of years ago. Mitochondrial DNA doesn’t change—it mutates very slowly.” He looked at Kegan. “Did you say all four bodies?”

“That’s right.”

“Then all four victims have a familial link. That could be huge.”

Danny looked at Nick. “I hate to have to ask this, but—why?”

“Motive, Danny—somebody knocked off four members of one extended family. It suggests some kind of family feud or something— that could narrow the field of suspects quite a bit.”

Danny turned to Kegan again. “What else did the tests show?”

“They’re running the DNA profiles through CODIS—the Combined DNA Index System—to see if they get a match with any unsolved cases. No results yet.”

“Well, let me know if you hear anything. Is there anything else?”

She glanced at Nick, who shook his head almost imperceptibly. “That’s all for now,” she said.

“Okay. You two get back to work—both of you. But keep me posted.”

When Danny was a safe distance away, Kegan leaned across the table to Nick. “I’m not going to cover for you, Nick.”

“You just did.”

“I mean I’m not going to keep doing it. Danny’s the boss—he has a right to know what’s going on—and by the way, so do I. We got the results on those two hair samples of yours. Are you going to tell me about them?”

“You first.”