Defending Jacob 2

Right now I am at the part where Jacob and his parents are in the court room talking to Jonathan. I am extremely surprised when Laurie, Jacobs mother, blurts out a comment against her own son. I know it is wrong if you lie in a very serious situation or defend someone while lying, but his mom told Jonathan about the "inherited violence disease" when that topic wasn't even on the subject. I am getting a feeling that Jacobs mom has a strong feeling that he was the murderer and she will not, under any circumstances, defend her son.