You knew she was going to kill her husband, and you had this Dr. Kammer here all ready for the nut alibi.
6 seconds sound clip from the After the Thin Man (1936) movie soundboard.
You can hear this line at 01:39:55 in the DVD version of the movie.
Quote context
[...]
- Were you ever in this room before?
- No.
- Why, of course not! What do you think...
- She had this room, and you knew about it.
- There's another mental case, right there.
[...]