Bellefonte, PA -- Michael McQueary, on administrative leave from his job, said he entered the Penn State football locker room in February 2001 to put away a pair of new sneakers and immediately heard "smacking sounds of skin on skin."
McQueary said the showers were on when he proceeded to his locker and caught a glimpse in a locker room mirror of a naked Sandusky. The front of his body was up against the back of a young boy whose hands were placed on the shower wall.
"I thought maybe I wasn't seeing what I was seeing," McQueary said. "Sandusky's arms were wrapped around the boy's midsection. I was extremely alarmed, extremely flustered."
He said he then stepped three to five feet into the shower area and "looked directly into each of their eyes."
McQueary said he put his shoes in the locker and slammed it shut, hard.
"I made the loud noise in an attempt to say 'Someone's here! Break it up!' " McQueary said.
When asked what he saw, McQueary said "the defendant's midsection was moving" subtly.
By the time he left the locker room, McQueary said, Sandusky and the boy, who he estimated to be 10 to 12 years old, had separated.
"I didn't expect to see anything like that ever," he said.
Asked by prosecutors why he left the locker room immediately, McQueary said: "I wasn't thinking 100% right.
"It was more than my brain could handle," he said. "I was making decisions on the fly. I picked up the phone and called my father to get advice from the person I trusted most in my life, because I just saw something ridiculous."
He said he was very vague with his father on the phone, and that his dad, John, told him to leave immediately and come to the house.
McQueary said he discussed the incident with his father and a family friend, both of whom urged him to report the incident to then-head football coach Joe Paterno.
Sandusky, 68, faces 52 criminal counts related to alleged assaults involving 10 boys over a 15-year span.
Earlier in the day, the alleged victim of Sandusky who launched the child-sex abuse inquiry recounted how Sandusky reportedly assaulted him over nearly four years beginning when he was 11 years old.
The witness, now 18, broke down briefly when he detailed the first time Sandusky forced him to perform oral sex in the basement bedroom of Sandusky's State College, Pa., home.
"He sat there (on the edge of the bed) and looked at me and said 'now it's your turn,' " the witness said, his face beginning to contort in pain. "He made me put my mouth on his privates. I don't know how to explain it. My mind wanted me to move, but I couldn't move."
After the encounter was over, the witness said Sandusky "looked at me and walked away."
"There were a million things running through my mind," he said.
The teen was the second of Sandusky's accusers to testify in the former coach's high-profile child sex abuse trial that began Monday.
During the testimony, Sandusky looked at the witness, at times resting his chin on his left hand. At one point, as the witness was recounting explicit sexual encounters with the coach, Senior Deputy Attorney General Joe McGettigan stared at Sandusky who was seated just a few feet away.
The witness, wearing a light open-collar shirt, said he met Sandusky about seven years ago when he was referred to the The Second Mile charity that Sandusky founded for at-risk children.
He said his contact with Sandusky began with innocent outings like basketball and summer camp before he was invited to spend nights at Sandusky's home. During summers he said he spent days at a time at the coach's home in the basement. He said that on 80%-90% of those nights Sandusky would engage in some sexual conduct with him.
It always began, he said, with Sandusky allegedly cracking the boy's back and moving his hands into the boy's pants. At various times during testimony the witness stopped, his head bowed and his voice shaking.
He said he began to distance himself from Sandusky in 2008, but Sandusky aggressively pursued him with telephone calls and unplanned visits. On one occasion, he said Sandusky followed his school bus from a local high school and confronted the boy about why he was avoiding him. The incident ended when the witness said he took off running with Sandusky following him in his car.
During cross-examination, Defense Attorney Joe Amendola repeatedly questioned why the witness had provided conflicting statements to Pennsylvania authorities and a state grand jury about the frequency of alleged abuse.
Some accounts, Amendola said, varied from reports that Sandusky had engaged him in oral sex more than 20 times, to accounts early in the investigation that there was no sexual abuse.
With each exchange, the witness became more emotional, one covered his face with his hands, before conceding that he "may have white-lied to try to cover embarrassment."
"I am here now telling the full truth," he said. "I didn't want anything bad to happen. There was a lot of stress in me to not say what happened. But I knew that if I am gonna grow up and put this behind me, the truth has to be told."
Again peppered with questions about his conflicting accounts, the witness appeared to look to prosecutors for assistance.
"Oh, my God," he called out. "I'd like you to stop asking me the same questions.
"I was scared," he said. "I didn't want to tell anybody (about what happened)."
With Sandusky at his side, Amendola went on to question the witness about possible motives in testifying against the former coach.
"Have you or your Mom ever told anybody you were going to get rich out of this thing with Jerry Sandusky?" the defense attorney asked, referring to potential civil lawsuits he may be considering against Sandusky or Penn State.
"Did you ever tell somebody you were going get a big house and a nice car out of this?" Amendola continued.
"I have dreamed about being in a big house," the witness said. "I have dreamed about having a nice car. Doesn't everybody?"
But he denied that was his motive for testifying against the coach.
The witness said he provided the first reports of the alleged abuse to local school officials in November 2008. He said those officials initially counseled him and his mother to "think about" their decision before pressing charges against Sandusky, who they said had "a heart of gold."
"They didn't believe me," the witness said, adding that his mother then took him to Pennsylvania social services officials who launched the formal investigation.
Jessica Derschel, a counselor with the Clinton County Youth Services office, said that following the second interview with the boy, she believed he had been abused.
During her first interview with the boy, she said it was apparent that "he was withholding (information) because he was uncomfortable."
On Monday, another alleged victim told jurors that he was forced into about 50 sexual encounters by Sandusky during the course of five years, beginning when he was about 12 years old.
Now 28, the witness said that his interactions with Sandusky escalated from friendly trips and "soap battles" in the showers of a Penn State locker room to inappropriate touching, then in 1997 veered into dozens of incidents of oral sex.
The witness said that when he tried to distance himself from Sandusky - they first met when the then-12-year-old was participating in programs run by Sandusky's charity - the coach became upset. The witness said later efforts to end contact brought "creepy love letters" in which the coach professed his deep feelings for the boy.
The letters, some hand-printed or written on Penn State stationery, were projected onto a screen. In one, Sandusky refers to "mistakes" before writing "love never ends."
Saying he wanted to "bury forever" the memories, the witness said he agreed to testify only after police "hunted me down." He said he later agreed to provide details to a grand jury after learning that others said they had been victimized by the coach.
"I feel if I just said something back then - I feel responsible for what happened to other victims," he said. He said he sometimes tried to resist the alleged advances, but he never confronted the coach. "I didn't want to lose everything," he said, referring to gifts, trips, cash and access to Penn State football that Sandusky provided. "I was too scared."
The witness said the coach asked him to sign contracts, promising him up to $1,000 for college if he agreed to remain in exercise and study programs monitored by the coach.
When Amendola suggested that the witness had hired a lawyer to pursue a lucrative civil lawsuit against the coach and the university, the witness said he had "never" discussed such a possibility.
Judge John Cleland had ruled earlier that the alleged victims would be identified in court, but USA TODAY generally does not name people claiming sexual abuse.
Cleland has said the trial could take three weeks.