abc s jim avila has more. reporter: abc news confirmed that jerry sandusky s 33-year-old adopted son, matt, until now his biggest supporter, has turned on his dad and offered to testify that he was personally abused by jerry. that s matt ducking into court. his attorney released this statement saying, during trial last friday he arranged a meeting with prosecutors to disclose for the first time in this case that he is a victim of jerry sandusky s abuse. matt took his own children to visit jerry early in the case, over the objections of their mother. and began this trial just ten days ago seated right next to his adopted mother dottie. visibly supporting sandusky. so why didn t prosecutors call him to testify? sources familiar with the case tell abc news, matt was waiting in the wings in case sandusky decided to testify. and then could be used as a rebuttal witness. you put a witness like that