Tale of Two Murders

A strange man was Stephen Gazeley; he could be witty, delightful and amusing. But on other occasions, as his sister Hilda knew very well, the familiar features would darken and he would snarl at those who dared to cross his path. One such person was his daughter, Katherine, engaged to Colin Luckett. Her father was obviously against the match. But why couldn't Hilda trust his civil politeness to Colin? What malicious thoughts and plots did it conceal?