Not " I KNOW he's guilty ?" Which would have been more precise.
Why are you nitpicking? She believes he is guilty, he statements from that time clearly show that. She says she still believes he is, of course she does, why wouldn't she?
These are the same games people played with Colin, acting as if they can read between the lines that he wrote in his book and that he has doubts. It wasn't until recently, when Colin spoke out saying that he DOES believe Bamber guilty, that the games stopped but now it seems they have begun with Julie!! The
prosecution witness!!!

Colin believes Bamber guilty.
Julie believes Bamber guilty.