You ought to know. Duke said you belonged to the same troop.
3 seconds sound clip from the The Enforcer (1951) movie soundboard.
You can hear this line at 00:30:36.703 in the Blu-ray version of the movie.
Quote context
[...]
- You see this? This was Smiley's. He carried an ice pick, too. Do all your friends carry ice picks?
- Take it away. I don't want to see it.
- He said he knew you. He said you made him kill his girl.
- I don't know what you're talking about.
- You know what a contract is? Do you know what a hit means?
- No, no.
- You ought to know. Duke said you belonged to the same troop.
- What is a troop? What kind of a troop?
- I can't talk. I can't tell you. I'm afraid.
- Yes?
- I'm sorry to have to bring you here at this hour, Mrs. Lazich.
[...]