Castle, Season 1

[after Brent tells Beckett his alibi]

Brett:
Am I under arrest or something?

Beckett:
No. You can go. But, just don't leave town until we speak again. Do you understand?

Brent:
Yeah. Yes, ma'am.

[after Brent leaves the interrogation room]

Castle:
"Don't leave town"? Don't you need probable cause for something like that?

Beckett:
Only he doesn't know that, does he?

Castle:
You can lie like that? That is so cool. [begins taking notes]