The Apprentice: A Rizzoli & Isles Novel

vision of packaged tarps hanging in Wal-Mart, the manufacturer’s suggested uses printed on the label: PERFECT FOR CAMPING, WEATHERPROOFING, AND WRAPPING DEAD BODIES .
    “If it’s just a tarp, we’re dealing with a pretty generic piece of fabric,” said Rizzoli.
    “C’mon, Detective. Would I drag you over here to look at a perfectly generic fiber?”
    “It’s not?”
    “It’s actually quite interesting.”
    “What’s interesting about a nylon tarp?”
    Erin reached for a folder on the lab countertop and pulled out a computer-generated graph, on which a line traced a silhouette of jagged peaks. “I ran an ATR analysis on these fibers. This is what popped out.”
    “ATR?”
    “Attenuated Total Reflection. It uses infrared microspectroscopy to examine single fibers. Infrared radiation is beamed at the fiber, and we read the spectra of light that bounces back. This graph shows the IR characteristics of the fiber itself. It simply confirms that it’s nylon six, six, as I told you earlier.”
    “No surprise.”
    “Not yet,” said Erin, a sly smile playing at her lips. She took a second graph from the folder, laid it beside the first. “Here we see the IR tracing of exactly the same fiber. Notice anything?”
    Rizzoli gazed back and forth. “They’re different.”
    “Yes, they are.”
    “But if these are from the same fiber, the graphs should be identical.”
    “For this second graph, I altered the image plane. This ATR is the reflection from the
surface
of the fiber. Not the core.”
    “So the surface and the core are different.”
    “Right.”
    “Two different fibers twisted together?”
    “No. It’s a single fiber. But the fabric has had a surface treatment. That’s what the second ATR is picking up—the surface chemicals. I ran it through the chromatograph, and it seems to be silicone-based. After the fibers were woven and dyed, a silicone rub was applied to the finished fabric.”
    “Why?”
    “I’m not sure. Waterproofing? Tear resistance? It must be an expensive process. I think this fabric has some very specific purpose. I just don’t know what it is.”
    Rizzoli leaned back on the lab stool. “Find this fabric,” she said, “and we’ll find our perp.”
    “Yes. Unlike generic blue carpet, this fabric is unique.”

    The monogrammed towels were draped over the coffee table for all the party guests to see, the letters AR , for Angela Rizzoli, entwined in baroque curlicues. Jane had chosen them in peach, her mother’s favorite color, and had paid extra for the deluxe birthday gift wrapping with apricot ribbons and a cluster of silk flowers. They’d been delivered specifically by Federal Express, because her mother associated those red, white, and blue trucks with surprise packages and happy events.
    And Angela Rizzoli’s fifty-ninth birthday party should have qualified as a happy event. Birthdays were a very big deal in the Rizzoli family. Every December, when Angela bought a fresh calendar for the new year, the first thing she did was flip through the months, marking the family’s various birthdays. To forget a loved one’s special day was a serious transgression. To forget your
mother’s
birthday was an unforgivable sin, and Jane knew better than to ever let the day slip by uncelebrated. She’d been the one to buy ice cream and string up the decorations, the one who’d sent out invitations to the dozen neighbors who were now gathered in the Rizzoli living room. She was the one now slicing the cake and passing the paper plates to guests. She’d done her duty as always, but this year the party had fallen flat. And all because of Frankie.
    “Something’s wrong,” Angela said. She sat flanked on the couch by her husband and younger son, Michael, and she stared without joy at the gifts displayed on her coffee table—enough bath oil beads and talcum powder to keep her smelling sweet into the next decade. “Maybe he’s sick. Maybe there’s been an accident and nobody’s called me yet.”
    “Ma, Frankie’s fine,” said Jane.
    “Yeah,” Michael chimed in. “Maybe they sent him out on—what do you call it? When they play war games?”
    “Maneuvers,” said Jane.
    “Yeah, some kinda maneuvers. Or even out of the country. Some place he’s not supposed to tell anyone about, where he can’t get to a phone.”
    “He’s a drill sergeant, Mike. Not Rambo.”
    “Even Rambo sends his mother a birthday card,” snapped Frank Senior.
    In the sudden hush, all the