Harry Potter (goblet of fire) Question?

So I am reading Harry Potter and the Goblet of Fire....got a little confusing when I tried to recount what happened. Here is the question: I remember somewhere in the book Sirius or Moody or SOMEONE was telling harry that Mr. Crouch's son gave a list of names of Death Eaters. I know that Harry witnessed the trial but who was the person in the book that first told Harry that Mr. Crouch's son had done this?!?! It annoying me! Also, I remember this person said it made him quite "unpopular." Please someone help! Who was the person that told harry about Crouch's son giving away names?!