Run to Evil — Dell Shannon

The neighbours all said ten-year-old Paul Brandon would grow up to be a detective: he was remarkably observant and inquisitive. But Paul doesn't grow up to be a detective; after failing to return one night, his body is found buried under a road excavation site. A tragic, unnecessary accident it seems.

But after the foreman insists that no child could move that amount of earth, Vic Varallo begins to suspect foul play and follows the leads to Paul's reticent playmate Gordon, who may have witnessed something terrible that night.

'My favourite American crime-writer' New York Herald Tribune