movie where a character hums before committing murder

The infamous story of Benjamin Barker, a.k.a Sweeney Todd, who sets up a barber shop down in London which is the basis for a sinister partnership with his fellow tenant, Mrs. Lovett. Based on the hit Broadway musical.

It is England in the 1830s. London's dockside is teeming with ships and sailors who have made their fortune in foreign lands. Sweeney Todd, a Fleet Street barber, awaits the arrival of men whose first port of call is for a good, close shave. For most it will be the last time they are seen alive. Using a specially designed barber's chair, Sweeney Todd despatches his victims to the cellar below, where he robs them of their new found fortunes and chops their remains into small pieces. Meanwhile, Mrs Lovett is enjoying a roaring trade for her popular penny meat pies.

Humming centers around the relationship between a sound engineer and a supporting actor working on the post-production of an unfinished film, along with the anecdote of a deceased actor.

A series of crimes is being perpetrated around a famous singer. Strangely, during each of the crimes, the artist's voice is heard humming his favorite song. Suspicions lead to a chase through a nocturnal Paris, ending in a disused theater where the assassin has lured his final victim.