What drives attractive male cousins to rape and kill ten young women? Why do an altar girl and her boyfriend lure innocent victims into their customised torture van? Couples who kill comprise only twenty per cent of killers, but they often murder serially and are responsible for particularly inhumane deaths. Sadistic friends, psychotic sisters and an increasingly pathological mother-son team are amongst those profiled in this exploration of the world's most deviant duos. There are infamous British cases, such as the Moors Murderers and the Wests, as well as many equally disturbing but less well-known ones. In the third of this series, which focuses on the psychology of murderers, Carol Anne Davis explores the formative influences of these killers and their deadly dynamics. Comprising of thirteen in-depth case studies and exclusive interviews with experts and one of the Wests' surviving victims, ''Couples Who Kill'' provides an unequalled study of this disturbing subject.