One Grave Too Many

with the others when a thought flashed through her mind. She looked at Frank. “I think I can tell you what he ate.”
    Frank looked shocked for a moment. “I was joking. You mean you can? From a bone?”
    “Not his last meal, but we may find a bit of information that might help identify him.”
    “How?” asked Kevin. “How can you tell what he ate by looking at his bone?”
    “You have to remove the collagen—that’s one of the components of bone—superheat it and turn it into gas so a mass spectrometer can detect the chemicals in the collagen.”
    “Wow. I really want to be a forensic anthropologist.”
    “Actually, the person I’m going to ask is a physical anthropologist. He studies bones too, among other things, but without the crime part. This is called stable isotope analysis. It’s the same method used to tell us the diet of Neanderthal man. We’re going to put one of the computer information programs about it in the primate exhibit.”
    “How do you tell what he ate?” asked Kevin.
    “Have you studied isotopes in school?”
    “Sort of.”
    “Then you know isotopes are like different species of atoms of the same element.”
    “Yeah . . .”
    “You know about carbon fourteen, used for dating objects. Carbon fourteen is an unstable isotope—it’s radioactive and decays over time. Because it decays at a constant rate, you can measure the decay to tell how old something is. It’s a little more complicated, but that’s basically it.”
    Kevin nodded. Diane was watching to see if his eyes were about to glaze over at all the science, but he listened attentively, so she continued.
    “Carbon also has two stable isotopes that don’t decay. So does nitrogen. And each has different ratios in the different types of foods—like vegetables, meats and fish. When we eat these things, the same ratios of the isotopes are absorbed in our bones, which means we can measure the ratios with a mass spectrometer and possibly find out what the person ate all his life. Like carbon fourteen tests, it’s more complicated, but you get the idea. Using it for this bone is a long shot. Most people in the U.S. have pretty much the same diet, but it could supply some more information about the individual. We might get lucky and he ate only red meat and potatoes all his life.”
    “Kevin, come here and look at this.” David Reynolds motioned his stepson to another of the computer animations. Kevin was reluctant to leave the conversation, but his mother, Cindy, pulled him away and went over to watch the mammoth animation with her husband.
    “That’s fascinating,” said Frank. “I’ll suggest it to the Rosewood police when I give them the bone.”
    “Did you get in touch with your friends?” asked Diane.
    He shook his head. “Not yet. I’ve been calling. I think George said he was going out of town for a couple of days. He should be back today, though. I’m going over there tomorrow.”
    They were interrupted by the muffled strains of “Ode to Joy” coming from Frank’s jacket.
    “Should have left this thing at home,” Frank mumbled. He stepped away from the others and answered his phone.
    Diane stole a glance at him and saw him drop his arms to his sides, lean on the column and put a hand to his face. She went over and touched his arm.
    “Frank?” asked Diane. “Are you all right?”
    He shook his head. “I have to go. It’s George and Louise. The ones with the missing daughter. The two of them and their son were found dead in their home.”
    “Dead?” whispered Diane. “How?”
    “I don’t know. I’m going over there. Look, Diane, I need to . . .”
    “It’s all right. Do what you have to do.” She walked him to the door. “I’m so sorry.”
    “I’ll call later. Tell Kevin I had to leave. Poor kid’s used to me taking off in the middle of things.” He kissed her cheek, and Diane watched him walk to the parking lot before she closed the door.
    Dead—a whole family gone. She put the flat of her palm on the door to steady herself. A missing daughter, and now this. A sudden tap on her shoulder made her jump.
    “I’m sorry, Doc.” It was Jake Houser, the security guard. “I didn’t mean to startle you.”
    “Is everything all right?”
    “Just fine. I wanted to tell you that I’ve been hearing the phone ringing in your office. I wouldn’t mention it, but whoever it is is persistent.”
    “Thanks. I’ll go look at the caller ID.”
    “Oh, and . . .” He grinned broadly.