About " The West Wing" (1)

[english-learner]

How do I understand the phrase " pick up the scent" in this context? Can you give me a few examples about how to use this phrase? Thanks a lot for your help!!!

CHRIS
C.J., has--

C.J.
But that shouldn’t stop you from asking them anyway. Chris?

CHRIS
Has the President had any reaction to Josh on the show?

C.J.
None that I’m aware of.

CHRIS
Do you know--

C.J.
Seriously, that’s it. I’ll get you wheels down time when I’ve got it. [continues to wall through the hallway and is intercepted by Toby]

TOBY
They’re picking up the scent.

C.J.
Billy is. The rest of ‘em are picking up Billy’s scent.

TOBY
Josh is gonna come to the coffee.

C.J.
Keep him cool.

[Tdol]

It comes from hunting- dogs pick up the scent of an animal and chase it, so when someone picks up the scent, they start to detect something.