FOUND AT PRIMARY CRIME SCENE-- BLACKWATER LANDING
 
 Kleenex with Blood
 
 Limestone Dust
 
 Nitrates
 
 Phosphate
 
 Ammonia
 
 Detergent
 
 Camphene
 
 FOUND AT SECONDARY CRIME SCENE-- GARRETT'S ROOM
 
 Skunk Musk
 
 Cut Pine Needles
 
 Drawings of Insects
 
 Pictures of Mary Beth and Family
 
 Insect Books
 
 Fishing Line
 
 Money
 
 Unknown Key
 
 Kerosene
 
 Ammonia
 
 Nitrates
 
 Camphene
 
 Davett scanned the list up and down, taking his time, eyes narrowing several times. A faint frown. "Nitrates and ammonia? You know what that could be?"
 
 Rhyme nodded. "I think he left some explosive devices to stop the search party. I've told them about it."
 
 Grimacing, Davett returned to the chart. "The camphene ... I think that was used in old lanterns. Like coal-oil lamps."
 
 "That's right. So we think the place he's got Mary Beth is old. Nineteenth century."
 
 "There must be thousands of old houses and barns and shacks around here.... What else? Limestone dust.... That's not going to narrow things down much. There's a huge ridge of limestone that runs all the way through Paquenoke County. It used to be a big moneymaker here." He rose and moved his finger diagonally along the map from the southern edge of the Great Dismal Swamp to the southwest, from Location L-4 to C-14. "You could find limestone anywhere along that line. That won't do you much good. But"--he stepped back, crossed his arms--"the phosphate's helpful. North Carolina's a major producer of phosphate but it's not mined around here. That's farther south. So, combined with the detergent, I'd say he's been near polluted water."
 
 "Hell," Jim Bell said, "that just means he's been in the Paquenoke."
 
 "No," Davett said, "the Paquo's clean as well water. It's dark but it's fed by the Dismal Swamp and Lake Drummond."
 
 "Oh, it's magic water," the sheriff said.
 
 "What's that?" Rhyme asked.