Only the Dead - Malcolm Hollingdrake

Meet DCI Cyril Bennett, a man with a passion for manners and efficiency, as well as an eye for the ladies. His partner, DS David Owen, is naIve and untidy but keen. Together they make a formidable pair.
When the discovery of two infants' bodies is made at a Teacher Training College, Bennett and Owen are given the case. Soon a number of suspects is identified. At the same time, a killer is on the loose staging attacks using sulphur mustard.
Is there a link between the infants' bodies and the sulphur mustard attacks?
Do the answers lie in the past or the present?
Bennett and Owen must work together to bring to justice a killer with revenge on his mind.