So I've read through all his posts, and as he said himself, most of the people he has found suspicious have died.
He did talk about Faris, Wedge and Rydia a fair bit (as they were roleclaimers at the time of some of his posts), so it is possible that he investigated them and they came up clean? (he was initially suspicious of Faris and Wedge and later dropped it)
This would reflect Lelia's investigations as well, though this still doesn't rule out Lawyer, 2nd Godfather (crazy, I know, ok?), or the possibility that an SK will only be guilty for an FBI agent.

The main thing here is that Balthier likely investigated Wedge (as he was initially suspicious of him), and Wedge likely came up clean (as Balthier seemed to speak more highly of Wedge yesterday). So unless the mafia has some sort of really annoying ability to PM people (see Mailmain, Courier or Whisperer), this confirms Wedge's innocence and his role.