The Wages of Sin - Unquiet Spirits, #1

Charles Latham, wastrel younger son of the Earl of Clitheroe, returns home drunk from the theatre to find his father gruesomely dead. He suspects murder. But when the Latham ghosts turn nasty, and Charles finds himself falling in love with the priest brought in to calm them, he has to unearth the skeleton in the family closet before it ends up killing them all.