BELLEFONTE, Pa. (AP) - A man who claims to have been the young boy seen being abused by Jerry Sandusky in a Penn State shower 15 years ago, a central episode in the sex molestation scandal that rocked the school, is expected to testify Friday in the ex-football coach's appeal of his conviction.

It will be the first time he has testified in the case.Lawyers for the 29-year-old man say he is the person who was identified during the 2012 Sandusky trial only as Victim 2 - the person assistant coach Mike McQueary has said he witnessed being sexually abused by Sandusky in 2001.But the lead prosecutor at Sandusky's 2012 criminal trial, now in private practice, has testified that he does not believe the man is the same person McQueary saw in the shower.Sandusky's lawyers argue their client did not get a fair trial in part because his legal team at the time mishandled the issue of Victim 2's identity and did not call him to the stand. Sandusky was a retired coach with gym privileges at the time of the shower assault. He was convicted on charges of abusing 10 boys, including Victim 2.Though the man who claims he was Victim 2 did not testify at Sandusky's trial, he later won a civil settlement from the university.The Associated Press generally does not identify the victims of sexual assault, and in this case, a victim advocate said the man has asked not to be identified.McQueary reported what he saw in the shower to then-head coach Joe Paterno, who alerted the athletic director and a school vice president. But Sandusky wasn't arrested until a decade later, after a prosecutor got an anonymous tip that led them to McQueary, leading to accusations of a high-level cover-up. University trustees later cited Paterno's handling of the complaint as one of the reasons he was fired in 2011. He died just months later.Joe McGettigan, the former prosecutor in the Sandusky case, said he doubts the man is Victim 2 because his accounts have changed over time, he appears too old to have been the boy in the shower and he did not provide certain details to investigators until after McQueary had told his own story in open court.Sandusky's lawyers have argued that McGettigan was referring to the man who says he was Victim 2, and therefore lied to jurors, when he said during the closing argument that Sandusky's victims included "others presently known to God but not to us."The man who says he is Victim 2 told police in September 2011 that no abuse had occurred and said much the same to an investigator working for Sandusky's lawyers around that time. He subsequently hired a lawyer and changed his story, saying he had been sexually abused.Neither he nor Penn State has described the claim he made against the university that won him a settlement.During testimony in August, his attorney, Andrew Shubin, cited attorney-client privilege and would not answer when asked if he had ever tried to hide the man's whereabouts from police and prosecutors.Sandusky, who is serving a prison sentence of 30 to 60 years, is seeking to get his conviction overturned or a new trial under Pennsylvania's Post-Conviction Relief Act. That law is limited to allegations of newly discovered evidence, constitutional violations or ineffective counsel.