The Keeper of Secrets

This historical mystery by Judith Cutler is the first of a series featuring a newly ordained parson, Tobias Campion, who has taken a parish under the benefice of a rich distant cousin, Lady Elham.  He quikly manages to offend his patroness when he is moved to preach against the abuses of the poor by the landed gentry, even though he has recently come from just this group. This is considered a Regency period novel, post-Victorian, when some things are beginning to change in England but women are still largely subservient and the class system is still in full control, to the detriment of anyone not born to family wealth or a trade.
It is an odd collection of parishoners in Moreton St. Jude and Campion is floundering somewhat until he is befriended by Lady Elham's head housekeeper, Mrs. Beckles, and by the local doctor, Edmund Hansard. Mrs. Beckles finds Campion a competent housekeeper and serving girl and Campion also has the support of boyhood friend and now groom, Jem.
Much of the early story revolves around a convoluted situation in which Campion, Jem and a local man, Matthew, are all in love with Lizzie, Lady Elham's maid. Campion has rescued her from the unwelcome attentions of a friend of the Elham's son, and earned the young, soon-to-be Lord Elham's animosity for his pains.  Then a series of attacks, deaths, and disappearances create a building sense of apprehension in Campion. He is attacked by someone in the woods and left for dead. A local man, poaching for desperately needed food for his family, is caught in a "man-trap" and dies as a result of his injuries. The lord of the manor ostensibly drowns, leaving Campion's cousin a widow, and the violent and sadistic younger Elham in charge. Lady Elham and her son, however, respond to the death by largely vacating the premises for their other houses and estates and, as a result, the contested Lizzie is also absent, leaving the three men heart-broken. When Lizzie subsequenly goes missing and is finally found murdered in Campion's woods, Hansard and Campion set out to find the perpetrator of the murder, and, believing Lady Elham to have been deceived and unaware of Lizzie's death, to track her down and inform her of events.
The secrets they uncover are shocking and, although you may have suspected early on that Lord Elham had some help into the next world, the complexity of the motivations for murder will still be a surprise.  You can read Judith Cutler's own summary here.