The Twelfth Card

Davis, from the K9 unit, and her dog Vegas. Most police dogs were German shepherds, Malinois and—for bomb detail—Labrador retrievers. Vegas, though, was a briard, a French breed with a long history of military service; these dogs are known for having keen noses and an uncanny ability to sense threats to livestock and humans. Rhyme and Sachs had thought that running a 140-year-old crime scene might benefit from some old-fashioned search methods, in addition to the high-tech systems that would be employed.
    The engineer, Yu, nodded at the building that had been constructed on the site where Potters’ Field tavern had burned. The date on the cornerstone read 1879. “To build a tenement like this back then they wouldn’t have excavated and laid a slab. They’d dig a perimeter foundation, pour concrete and set the walls. That was the load-bearing part. The basement floor would have been dirt. But building codes changed. They would’ve put a concrete floor insometime early in this century. Again, though, it wouldn’t be structural. It’d be for health and safety. So the contractors wouldn’t’ve excavated for that either.”
    “So the lucky part is that whatever was under there in the eighteen sixties might still be there,” Sachs said.
    Forever hidden . . .
    “Right.”
    “And the unlucky part is that it’s under concrete.”
    “Pretty much.”
    “A foot deep?”
    “Maybe less.”
    Sachs walked around the building, which was grimy and plain, though she knew the apartments in it would rent for $4,000 or so a month. There was a service entrance in the back that led below ground to the basement.
    She was returning to the front of the structure when the phone rang. “Detective Sachs.”
    Lon Sellitto was on the other end. He’d found the name of the building’s owner, a businessman who lived several blocks way. The man was on his way to the place to let them inside. Rhyme came on the phone a moment later and she told him what Yu had said.
    “Good luck, bad luck,” he said, the scowl clear. “Well, I’ve ordered an S and S team there with SPR and ultrasound.”
    Just then the owner of the building arrived, a short, balding man in a suit and white shirt open at the collar. Sachs disconnected the cell call with Rhyme and explained briefly to the man that they needed to examine the basement. He looked her up and down suspiciously then opened the basement door and stood back, crossing his arms, near Vegas.The police dog didn’t seem to like him very much.
    A Chevy Blazer pulled up and three members of the NYPD Search and Surveillance Unit climbed out. S and S officers were a mixed breed of cop, engineer and scientist, whose job was to back up the tactical forces by locating perps and victims at scenes with telescopes, night vision imagers, infrared, microphones and other equipment. They nodded to the crime scene techs and then unloaded battered black suitcases, very much like the ones that held Sachs’s own crime scene equipment. The owner watched them with a frown.
    The S and S officers walked down into the dank, chill basement, smelling of mold and fuel oil, followed by Sachs and the owner. They hooked up probes that resembled vacuum cleaner heads to their computerized equipment,
    “The whole area?” one asked Sachs.
    “Yup.”
    “That’s not going to hurt anything, is it?” the owner asked.
    “No, sir,” a tech replied.
    They got to work. The men decided to use SPR first. Surface Penetrating Radar sent out radio waves and returned information on objects it struck, just like traditional radar on board a ship or airplane. The only difference was that SPR could go through objects like dirt and rubble. It was as fast as the speed of light and, unlike ultrasound, didn’t have to be in contact with the surface to get a reading.
    For an hour they scanned the floor, clicking computer buttons, making notations, while Sachs stood to the side, trying not to tap her foot or fidget impatiently, figuring that it wouldn’t be good for the instrument’s readings.
    After they’d swept the floor with the radar, theteam consulted the unit’s computer screen and then, based on what they learned, walked around the floor again, touching the ultrasound sensor to the concrete in a half dozen areas they’d targeted as important.
    When they were finished they called Sachs and Yu over to the computer, flipped through some images. The dark gray screen was unreadable to her: It was filled with blotches and