It's already built up.
3 seconds sound clip from the The Roaring Twenties (1939) movie soundboard.
You can hear this line at 01:31:41 in the DVD version of the movie.
Quote context
[...]
- The days of the rackets are over.
- I know you take your job very seriously, and I'll give you some good advice.
- The papers say the district attorney's office is building up a case against our friend George.
- You remember what George said would happen if you talked?
- If I don't see you again, merry Christmas.
[...]