In the opening of The Stepfather (2009) The character switches on children singing 'Silent Night' howver, the sweet angelic song is embedded with odd creepy music which portray the characters sick twisted mind.
As it is asthough he targets something innocent and makes it mortifying.
PLACE THE OPENING OF THE STEPFATHER HERE
In the movie 'HIDE AND SEEK' I saw that there was a creepy piano instrumental throughout and maybe the use of string instruments. As the film goes on , the music gets louder and faint voices of the characters re heard but you can still hear the music.
(HIDE AND SEEK 2004)
Music plays a big part in not only thrillers but all movie openings as it suggest the genre and sets the mood for the film before it is fully watched .