I have been looking for a music piece, possibly a piano sonata or concerto (because I remember a version of the piece sung with a boys choir), that appears in Red Dragon 1h, 36m and 20s into the movie. It is the scene where Lecter is having the dinner in his cell, and occurs during chapter 15. It is not composed by Danny Elfman, nor is it in the ending credits, and I can not seem to find it anywhere on the internet. Can anyone help?

Is it possible it was at least arranged by Elfman, and therefore part of the score instead of the soundtrack?

I am pretty sure that there wasn't a separate releasal for the score and soundtrack. It was only released as one disk. If it was an arrangement than there is no note of it anywhere that I can find, and in the titles of the songs in the score would be some indication of the variation or arrangement of the original piece.