Movies · 1946
Oh, Eddie, you don't have anybody watching me, do you? Tailing me in a gray Plymouth coupe, maybe?
— Philip Marlowe · The Big Sleep

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The question begins as if the speaker is unsure about being followed, then names a very specific car. That detail makes the uncertainty sound pointed rather than innocent. The wording gives the other person an opportunity to deny the suspicion while suggesting there is already evidence behind it.
Context reviewed