Jerry Sandusky's son Matt recalled showering with his future adoptive father as a boy and pretending to be asleep to avoid being touched - memories that surfaced only recently, according to a police interview that details what are the earliest allegations yet of abuse by the former Penn State assistant football coach.

Matt Sandusky, now 33, said the abuse started at age 8, a decade before he was adopted by the once-heralded defensive coordinator, according to the interview, first reported Tuesday by NBC News.

''If you were pretending you were asleep and you were touched or rubbed in some way, you could just act like you were rolling over in your sleep, so that you could change positions,'' Matt Sandusky said in an excerpt played Tuesday on NBC's ''Today'' show. His attorneys confirmed the recording's authenticity to The Associated Press.

Jerry Sandusky was convicted last week of 45 counts of abusing 10 boys he met through the charity he founded - the same organization that introduced him to Matt Sandusky, who became his foster child. Jerry Sandusky's principal lawyer did not return messages Tuesday, and another lawyer said only that Matt Sandusky's allegations contradict testimony he gave to the grand jury whose charges put his father on trial.

Matt Sandusky did not reveal any abuse when he was initially questioned as a grand jury witness but did release a statement alleging past abuse as the jury was sequestered in deliberations last week.

The police interview tapes are the first time Matt Sandusky's allegations of sexual abuse have been publicly aired, and too much time has passed for criminal charges. Asked why he was now coming forward on abuse purported to have occurred as early as the late 1980s, Matt Sandusky told police there were several reasons - but singled out his family.