Burial Mound in Bloomington, MN

A Bronze-Age burial mound close to Stonehenge, an archaeological excavation. The expectation: an ancient body, historical artefacts. They did not expect to find a recent burial there as well.
It's another case for Detective Inspector Tremayne and Sergeant Yarwood. The more recent of the two bodies, the brother of the mayor of Salisbury.
The person responsible keeps leading back to the brother, the upright and serious-minded Clive Grantley. Tremayne's sure that it's him, but Clare Yarwood's not so sure.
But is her belief based on evidence or personal hope?