Jasper Night 3 Catoptromancy. Jasper Night Stories, #3

In book 3, Dark Angel, one of the Brotherhood's more senior operatives, alerts Jasper Night to the strange disappearances of up to sixteen people from the northern suburbs of Adelaide. These are people who have no link to each other but have one thing in common, their disappearance. In this episode, Jasper's investigation leads him to a strange conclusion, and he finds himself pitted against a demon that likes to inflict pain and death on humans, a beast from the darkest of places that should not exist on Earth.
He must rescue those it has stolen, if they are still alive, and then send the thing back from where it came or there will be more losses and suffering.