Cain His Brother by Anne Perry

Set in Victorian London, this gripping mystery follows private investigator William Monk as he delves into the disappearance of a wealthy gentleman, Angus Stonefield. The case takes a dark turn when Monk discovers that Angus's estranged twin brother, Caleb, a man with a notorious reputation, may be involved. As Monk navigates the murky waters of family secrets and societal expectations, he must confront his own past while unraveling a web of deceit and betrayal. The story explores themes of identity, loyalty, and the thin line between love and hate, all set against the backdrop of a richly detailed historical setting.