The Holy Thief written by Ellis Peters performed by Stephen Thorne on Cassette (Unabridged)

At the height of the hot summer of 1144, the Earl of Essex succumbs to a fatal arrow, but only after a lingering fever, during which his officials do their best to save him from hellfire by restoring various properties he has annexed, including the abbey of Ramsey.

And so it is that the envoys arrive at the abbey of St. Peter and St. Paul. Heavy rains bring the threat of flood: the holy relics must be saved. And when the waters subside, a robbery is revealed. And before Brother Cadfael can solve the case, to the crime of theft is added a murder.