Kind Hearts and Coronets (1949, UK)

In this morbid and black Ealing classic comedy about inheritance in Edwardian England by director Robert Hamer:

• the remarkable casting of Alec Guinness as all eight aristocratic D'Ascoyne family relatives, all pictured in the title screen (young and old, and male and female -- a General, a snob, a young photographer, a suffragette, an Admiral, a Reverend, a banker and the Duke) who stood in the way of cold-blooded serial killer and impoverished, embittered commoner Louis Mazzini (Dennis Price) - the ninth in line to inherit the Dukedom of Chalfont, who must murder all the other rival successors, to become the new Duke of D'Ascoyne
• the many tactics or circumstances of the deaths of his rivals: snobbish Ascoyne d'Ascoyne (by drowning in a boating accident), young Henry d'Ascoyne (by fire in a photographic darkroom), Reverend Lord Henry d'Ascoyne (The Parson) (by poison), suffragette Lady Agatha d'Ascoyne (by a fall in hot-air balloon), Admiral Lord Horatio d'Ascoyne (The Admiral) (not murdered, died in naval accident), General Lord Rufus d'Ascoyne (The General) (by bomb explosion), Lord d'Ascoyne Ethelred (The Duke) (by gunshot while caught in a trap), and Lord Henry d'Ascoyne, Sr. (The Banker) (by fatal heart attack)
• while in prison and about to be executed for a murder he didn't commit (of Lionel Holland (John Penrose)), the flashback of vengeful Mazzini to his earlier days: ("In those days, I never had any trouble with the Sixth Commandment") and a recounting of his parents: his opera-singing father died when seeing his newborn child for the first time, while his disinherited ostracized widowed mother (a member of the high-born D'Ascoyne family) was killed by a train (and refused a burial in the family vault at Chalfont)

Mazzini's Self-Incriminating Memoirs Left on Desk in Prison Cell

• in the satirical and memorable twist ending, Mazzini was released from prison to a cheering crowd (due to perjured testimony and a deal with the victim's widow Sibelia Holland (Joan Greenwood)); he was approached by a Tit-Bits reporter (Arthur Lowe) who asked: "Your Grace, I represent the magazine Tit-Bits by whom I'm commissioned to approach you for the publication rights of your memoirs"; Mazzini paused for a second, then replied: "My memoirs? Oh, my memoirs. My memoirs" -- he glanced backward, and was reminded that he had left a self-incriminating memoirs document on his desk in his cell - the camera tracked back to his cell and the pile of his papers that would reveal his guilt