Thielman, Mark. Johnson and Nance mystery

When a history professor is fatally shot at the base of Yellowstone Canyon, seasonal park ranger and former homicide detective Clarence Johnson finds himself roped into the murder investigation. Alongside Special Agent Alison Nance, he quickly realizes they are uncovering more than just a killer. As Johnson and Nance hunt for the killer, clues gleaned from the professor's research hint at a historic conspiracy involving an ancient relic believed to have been secreted away by royalists during the French Revolution. Their hunt through the wilds of Yellowstone leads them to realize that the professor's death and the missing artifact are intricately connected. But Johnson and Nance's suspects are disappearing at an alarming rate, pitting them in a race against time before those determined to do anything to protect the secrets of the past strike again