Joe noticed a strange odor in the air when the wind shifted. The odor was sickly sweet and metallic, and he winced when a particularly strong waft of it blew through.

Making sure Lucy was well behind them, Joe winked at Sheridan as he overtook her, and she fell in behind him as he closed in on the two fishers. He debated whether or not to show his badge before saying hello, and decided against it. Joe noticed the unpleasant odor again. It seemed to get worse as he walked upstream.

As he approached them, he felt Sheridan tug on his sleeve, and he turned and saw her point toward the water. A small brook trout, not more than six inches long, was floating on the top of the water on its side. It wasn't dead yet, and he could see its gills working as it pathetically tried to right itself and swim away.

"The fish killers," Sheridan whispered ominously at the man and woman in front of them, and he nodded to her in agreement.

The man looked to be in his late fifties, and was dressed as if he were a cover model for Fly-Fisherman magazine. He wore ultralight Gore-Tex waders and leather wading boots, a pale blue Cool-Max shirt, and a fishing vest with dozens of bulging pockets filled with gear. A wooden net hung down his back from a ring on his collar. A leather-bound journal for documenting the species and size of the fish he caught was on a lanyard on his vest, as was a small digital camera for recording the catch. The man was large and ruddy, with a thick chest. He had a salt-and-pepper mustache and pale, watery eyes. He looked like a hungover CEO on vacation, Joe thought.

Behind and off to the side of the man was a much younger woman with blond hair; long sunburned legs; and a fishing vest so new that the tag from the Bighorn Angler Fly Shop was still attached to the front zipper. She held her rod away from her body with the unease of someone holding a dead snake.