I read the book ages ago and have seen the film several times (enjoyed both) but I still can't figure out how Corliss was fed the info about Roulet. I know Gloria primed him but who did he speak to, what was in it for him to perjure himself and how did Mick know how to target him? Thanks in advance.
shareI'm not %100 sure, but it's probably Gloria.
When she approaches him while he's in the line, she says something around
Gloria: I talked to the DA, he gave me a way to get us both out
It's very simple.
Gloria approached him when he was in the line, and she says she might have a way to get us both out or something like that.
The viewers don't actually see Gloria and Corliss speak in private, but not everything has to be spoon fed to the viewers.
So it's safe to assume that Gloria told him what to say at court, and maybe they also offered him free defense, or cash or whatever.
The Snitch tells the DA (most likely through his lawyer), that he has testimony to kick Roulet's but into the chair. For that he would get a deal, maybe even get his charges dropped. To go by his history as revealed in court, he would well know ho to go about it.
Mick got the tip about The Snitch from his ex-wife. She was kicked from the case because of their relationship (explained in detail in the book). After that, he sent one of his investigators to look into the guy's history.
When finding out that the DA had The Snitch "parked out of reach", Mick realized he had a client in the same place.
And so Mick had a golden opportunity: he could get Roulet off on the charges he defended him against and at the same time make sure Roulet would get it for the other case, which would also see his former client exonerated.