Plot giveaway?
When they first meet with Kobayashi, he (Kobayashi) mentions all their names and how he was familiar with them...except Verbal. He says something like "I take it you must be Mister Kint, the man who shot Saul".
The only way Kobayashi would know that is through Verbal himself. No one survived the heist, they never told Redfoot who killed Saul...so how else would he know?
Here is the actual script for this scene:
"I am Mr. Kobayashi. I've been asked by my
employer to bring a proposal to you
gentlemen. That must be Mr. Hockney. I
recognize Mr. Fenster from his mug shot,
as well as Mr. McManus.
(To Verbal)
I can only assume that you are Mr. Kint.
I believe you were the one who disposed
of Saul. My employer sends his gratitude.
A most unexpected benefit."
http://www.imsdb.com/scripts/Usual-Suspects,-The.html