Matt Sandusky police tapes detail alleged sex abuse by father, Jerry (VIDEO)

On the eve of Jerry Sandusky's child sex abuse trial, his adopted son told police in a taped interview that the former Penn State assistant football coach had molested him from age 8 to 15, NBC News reported.

Sandusky, 68 was convicted last week of 45 counts of child abuse and is in prison awaiting sentencing.

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In a 29-minute police interview obtained by NBC News, Matt Sandusky describes how he would curl up in a fetal position and pretend to be asleep when Sandusky would come into his room at night. The abuse was "like the showering, with the hugging, with the rubbing, with the just talking to me, the way he spoke," he said.

While being questioned by an investigator, Matt Sandusky said his adoptive father would blow raspberries on his stomach and touch his genitals, The Associated Press reported.

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He also said he was undergoing therapy, that his memories of abuse were only now surfacing and that he was coming forward so his family would know what happened.

Sandusky defense lawyer Karl Rominger said his client was "very upset" when he learned that Matt Sandusky had been prepared to testify as a rebuttal witness if Jerry Sandusky took the stand. He also challenged Matt Sandusky's portrayal of events, according to NBC News.

Quoting from the tape, Rominger ABC News that at one point Matt Sandusky expressed concern that he could face perjury charges because his claims contradicted his earlier statements to the grand jury.

Matt Sandusky was adopted by Jerry and Dottie Sandusky at age 18. The couple has five other adopted children, four of whom of are males, the Allentown Morning Call reported.

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