The Night Killer

saw Liam cross the creek at a narrow point and proceed out of sight. She went back to collecting blood samples. She found a fiber stuck under a spot of dried blood on the tree. She lifted it and put it in an envelope. Neva was drawing the scene as she and Frank measured the distance between objects. All in all, they were going pretty fast.
    Diane had taken her last sample and Neva was examining the pan and lifting prints when they heard shouts downstream from Mike and Liam.

Chapter 49
    When Diane and the others found Mike and Liam, they were on the bank looking at an object under the water. Diane squatted for a closer look. It was a leather drawstring pouch about the size of a cantaloupe wedged between two large rocks of about the same size as the pouch. Water flowed around and over it. Diane could see from the contours of the bag that there was something in it.
    Diane photographed it from several angles. Neva set about drawing it while Frank got Mike to help take measurements.
    “See, we were quite helpful,” said Mike.
    “Yes, you were. This is only about forty yards from the primary site. What took you so long to find it?” said Diane.
    “Is she always this exacting to work for?” Liam asked Mike.
    Neva grinned. Mike made a face back at her.
    “I assure you, Liam, Mike is more demanding in his department than I am in the whole museum,” said Diane. “Now, what did you do, miss it the first time and find it on the return trip?”
    “There was a glare on the water,” said Mike. “I missed it. And yes, we were coming back when we found it.”
    “We both missed it the first time,” said Liam. “He’s right. With the glare, we couldn’t see under the flowing water.”
    “Just wondering,” said Diane, stifling a smile.
    When she and Neva finished recording the find, Diane rolled up her jeans and waded into the water to retrieve it. She had on latex gloves and the chill of the water came through immediately. It was colder than she expected and the phrase cold mountain stream came to mind. The drawstring of the pouch was hung up. Diane tried to push the rocks aside to release it. It proved harder than she expected, but she finally unseated one of the rocks and the pouch came free.
    Diane waded out of the water to the bank. Neva had spread out a large envelope she had cut open to make it even larger.
    “I thought you’d want to see what was in it right away,” said Neva.
    “You did, did you?” said Diane.
    The four of them—Frank, Mike, Neva, and Liam—gathered around Diane as she opened the bag. Diane sniffed it first, just to make sure it wasn’t something unpleasant, like someone’s old lunch. Not much of a smell. She looked inside. It looked like rocks. She poured the contents out on the paper Neva had provided.
    A glittering array of what appeared to be gold nuggets tumbled out onto the paper. The stones were mostly solid gold but some were clearly quartz with gold flecks.
    “Well, I’ll be,” said Liam. “They did find gold—I suppose this is theirs.”
    “No,” said Mike, “it’s not gold. It’s pyrite. Or, as some call it, fool’s gold.”
    “It’s not gold?” said Neva.
    Mike looked over at her. “And here I thought you’d spent a lot of time studying my reference collection in the museum,” he said.
    Neva rolled her eyes. “Every chance I get,” she said.
    “It’s pyrite—iron sulfide,” he said.
    He took a slender stick and divided up the rocks.
    “These shiny square pieces are pyrite in its isometric crystal habit.”
    “What’s that in layman’s terms?” asked Liam.
    Mike smiled at him. “Crystal pyrite. This piece here that’s amorphous in shape is what’s called massive pyrite.”
    “What about this?” Liam pointed to the quartz that had the gold flecks.
    “Pyrite in quartz,” said Mike. “Like gold, pyrite often occurs in combination with quartz.
    “No gold?” said Liam.
    “Gold is also found in association with pyrite,” said Mike, “but I don’t see any here in this cache.”
    “I hope they weren’t killed over this,” said Frank.
    Mike stood up and walked to the creek to an accumulation of sand that had been dropped by the flowing water where it slowed down in a curve. He scooped up a handful of the sand and came back. Over the grassy bank of the creek he picked through the wet sand in his palm.
    “We’ve got a lot of quartz, feldspar, magnetite—that’s these black grains. When you’re panning for gold you look for magnetite.