Mystery in the Ravine — Carol J. Farley

When Kipper and Larry set out to explore the ravine on the edge of town, Kipper thought it looked eerie. But there was nothing really mysterious about it until they met a man who said he was digging for Mohawk Indian artifacts… And then they saw a body!

Both boys knew that the Mohawks had never lived around Ludington, Michigan, and what's more when they climbed the ridge to get a good look at the body, it had disappeared! Something might peculiar was going on and the boys decided to get to the bottom of it.