Not quite Forensic Linguistics (or maybe it is?)

So we were watching Castle yesterday. Surprisingly enough, German TV is for once reasonably close to the original run, so we're actually in Season 4. Woo hoo.

Anyway, it was the episode with the Bank Robbery that Feels Fishy. Something beyond the bank robbery felt fishy to me.

( Cut for potential spoilers for Castle S4 Ep7 )

Anyone else have that problem? Or am I linguistically hypersensitive?
(Rhetoric question. I know I'm linguistically hypersensitive. OR MAYBE EVERYONE ELSE IS HYPOSENSITIVE! [/fëanor])