Lawyers for Matt Sandusky, one of six children adopted by the Sanduskys, said the 33-year-old had told authorities his father sexually abused him and that he had been prepared to testify on behalf of prosecutors at his father's trial.
"During the trial, Matt Sandusky contacted us and requested our advice and assistance in arranging a meeting with prosecutors to disclose for the first time in this case that he is a victim of Jerry Sandusky's abuse," said a statement issued Thursday by lawyers Andrew Shubin and Justine Andronici. "At Matt's request, we immediately arranged a meeting between him and the prosecutors and investigators.
"This has been an extremely painful experience for Matt and he has asked us to convey his request that the media respect his privacy. There will be no further comment."
Jerry Sandusky faces 48 criminal counts involving the abuse of 10 boys over a 15-year span.
Sources close to the case told ABC News that Matt Sandusky -- who had defended his adoptive father throughout the investigation -- contacted prosecutors late last week to say that he was willing to testify. Prosecutors couldn't call him to the stand for direct questioning because he was not included in the charges against his father.
But they could have called Matt Sandusky to the stand as a rebuttal witness if Jerry Sandusky took the stand, sources said.
Matt Sandusky went to live with Jerry Sandusky and his wife, Dottie, as a foster child and was adopted by them as an adult. He attempted suicide several months after moving in with Sandusky in 1995.
In addition, Matt Sandusky's wife got an order of protection on behalf of their children against the elder Sandusky shortly after his November arrest.
The jury of seven women and five men began deliberating the case Thursday afternoon after lawyers delivered lengthy closing arguments. They are being sequestered during their deliberations and are expected to work through the weekend if they have not returned a verdict by Friday.
In closing arguments, prosecutors described Jerry Sandusky as "a serial, predatory pedophile" who groomed his victims. They said he used his position to lure and abuse vulnerable boys.
"He molested and abused and hurt these children horribly," said Senior Deputy Attorney General Joseph McGettigan III. "He knows he did it, and you know he did it.
"Find him guilty of everything."
Defense attorney Joseph Amendola said 68-year-old Sandusky was being victimized by an overzealous prosecution and greedy accusers. He yelled that there was no way the investigation into Sandusky was fair or the allegations against him are credible, saying investigators pressured witnesses into making false claims.
Amendola alleged that investigators were out to get Jerry Sandusky and were ruining his reputation and life.
Sandusky's wife, Dottie, and adopted daughter Kara were in the court for him, with Kara crying towards the end of Amendola's closing argument.
The closing arguments came after seven days of testimony, some of it graphically describing alleged touching in showers, fondling and in some cases, forced oral or anal sex.
Jerry Sandusky has denied any wrongdoing. If convicted, he could spend the rest of his life in state prison.
ABC News and The Associated Press contributed to this report.