A Taste for Malice — Michael Malone

DI Ray McBain is back at work and on filing duty. Desperate for something to do, a pair of old files intrigue him. In the first a woman pushes her way into a vulnerable family. The children adore her. At first. Then she has some "fun", which soon becomes torture and mental cruelty. Then she disappears. Meanwhile, in Ayrshire, another young family is relieved when a stranger comes into their lives to help them out. McBain makes the link, but nobody is interested in what he has to say. Is it even the same woman? This is the second novel to feature DI Ray McBain. Blood Tears was published in 2012.