Superintendent Lorrie Sullivan Series: A Brace of friends

A missing child, a spate of gruesome murders, and no clues. Not one killer but two.
Are these cases going to be the ones that finally flummox Superintendent Lorrie Sullivan?
A Brace of Fiends is the sixth book in the Superintendent Lorrie Sullivan series. In book six, the author introduces the reader to not one but two psychopaths and – this time – the serial killers are women.
Some say that women make the cruellest of killers. You be the judge.