Canyonlands Carnage (National Park Mystery)

"When suspicious deaths befall a whitewater rafting expedition through Cataract Canyon in Canyonlands National Park, archaeologist Chuck Bender and his family recognize evil intent lies behind the tragedies. They must risk their lives and act before the murderer makes an already deadly journey on the Colorado River through Utah's red rock wilderness even deadlier--or turns on them instead"--