Mortal Trespasses - a thriller by Geoffrey Sleight

A phone call from a terrified woman is abruptly terminated. Elliot
Delaney is torn between investigating the call, or ignoring it. But the
incident begins to stir distant memories of a couple he met once on
holiday, and he can't let it pass.

His search to uncover what lies behind the call draws him into a
dangerous, secretive world at a small, country church where strange
practices are taking place.

Elliot is joined by a woman who fears it may be a former partner whose
life is at risk at the church. As they begin to delve deeper into
shocking experiments taking place in the crypt, their own lives become
targets. And soon the markers between the living and the dead have
life-changing consequences for them.