BELLEFONTE, Pennsylvania (Reuters) - A former Penn State assistant football coach testified in the Jerry Sandusky child sexual abuse trial on Tuesday that he saw Sandusky naked in a campus locker room shower sexually molesting a young boy.

"There was no way that his genitals were not right up against that young boy's rear end," Mike McQueary, one of the most anticipated witnesses in the trial of Penn State's former football defensive coordinator, told the Pennsylvania jury of the 2001 incident.

Earlier in the second day of testimony in the closely watched trial, a sobbing 18-year-old witness called by the prosecution told jurors that Sandusky had befriended him as a boy and gradually began to abuse him sexually.

The witness said he met Sandusky when he was about 10 or 11 years old through the Second Mile charity that Sandusky founded. He described being sexually abused by Sandusky, including oral sex, adding, "I didn't want it to happen."

Sandusky is accused of using Second Mile, which he opened in 1977, to prey on needy young boys.

Sandusky, 68, faces 52 counts of abusing 10 boys over a 15-year period. If convicted on all counts, he faces a sentence of more than 500 years in prison.

The case shook Penn State and its long-successful football program, prompted the firing of legendary head coach Joe Paterno, and brought national attention to the issue of child sexual abuse.

Two witnesses in the trial have described being sexually abused by Sandusky as boys, and six more alleged victims are due to testify. McQueary was the first witness to tell jurors he saw Sandusky molesting a boy.

McQueary, then a graduate assistant football coach, testified in Centre County Court that he had gone to the Lasch Football Building on the Pennsylvania State University campus to drop off some shoes in his locker and do some work late on a Friday in February 2001.

When he entered the first of two doors in the staff locker room, he said, he heard "smacking sounds, very much skin-on-skin smacking sounds. I was embarrassed I was walking in on something," said McQueary, a red-haired former Penn State quarterback.

McQueary said that when he entered the locker room he could see into a shower reflected in a bathroom mirror. He told jurors he saw a naked boy, 10 to 12 years old, bracing himself against the shower wall. Sandusky, also naked, was behind him, holding the boy around the waist and moving against him, McQueary added.

McQueary said he saw them in the same position when he looked directly into the shower. Moments later, they were standing in the shower apart from one another, naked, directly facing him, McQueary said. The boy, known as Victim 2, has not been found by authorities.

McQueary said he returned home shaken, called his father and contacted Paterno the next day. Athletic Director Tim Curley and Gary Schultz, who as vice president for business and finance director was head of the school police, were also informed.

The incident was not reported to police or child protection services. Penn State's handling of it drew heavy criticism when the episode came to light in 2011.

Last November, Penn State's board of trustees fired Paterno and university President Graham Spanier for failing to act on the allegations. Curley and Schultz face charges of perjury and failure to report suspected abuse.

McQueary, who had become Penn State's receivers coach, was put on administrative leave. He was not rehired when coach Bill O'Brien was hired to replace Paterno, who died of cancer in January at 85.

Prosecutors allege that Sandusky had physical contact with the boys he is accused of abusing, known in court documents as Victims 1 to 10, that ranged from tickling and a "soap battle" in Penn State showers to oral and anal sex.

Defense attorney Karl Rominger questioned McQueary's testimony, pointing out discrepancies in accounts to police and a grand jury about the date of the alleged incident and at what point the boy had seen him. He also pressed McQueary on why he had not called police about the incident.

"In my mind, when I spoke to Mr. Schultz he was very much like a district attorney," responded McQueary, who said last month he planned to file a whistleblower lawsuit against Penn State.


Earlier on Tuesday, the 18-year-old witness, identified in court documents as Victim 1, testified that he began spending time at Sandusky's home in State College, home to Penn State, after attending Second Mile events.

Sandusky gradually grew more intimate with him until he would kiss him on the lips and blow on his bare stomach when the boy was ready to go to sleep in Sandusky's basement, the witness testified.

Then one day, "after cracking my back and rubbing his hands down the back of my shorts and blowing on the stomach, he, he put his mouth on my privates," the man said, holding back sobs as a silent courtroom listened.

"I didn't know what to do. With all the thoughts running through my head I kind of blacked out, I didn't want it to happen," the witness added.

The witness began to cry and said Sandusky later had forced him to put his mouth on the coach's genitals. "He said something along the lines of, 'It's your turn,'" the witness said, his head bowed.

The witness testified that Sandusky had performed oral sex on him several times and he had done it to Sandusky at least once. He said he had met Sandusky in 2005 or 2006 and broke off contact in early 2008.

The white-haired Sandusky sat hunched forward at the defense table, his back to the courtroom, as testimony went on.

Under cross-examination by defense attorney Joe Amendola, the witness was asked about discrepancies in his testimony. He had first told investigators in June 2009 that Sandusky performed oral sex on him more than 20 times, but five months later told a grand jury it was about 12 times.

The witness said he had been afraid the first time he talked to investigators and had resolved to tell the truth to the grand jury. He also denied that he and his mother had talked about getting rich from the Sandusky scandal.

Reuters' policy is not to identify victims of sexual crimes.

(Additional reporting by Matt Morgan in Bellefonte; Writing by Tom Brown and Ian Simpson; Editing by Paul Thomasch and Will Dunham)