(CNN) -- A Penn State assistant football coach who reportedly told Joe Paterno in 2002 he witnessed a young boy being sexually assaulted in a shower won't be at Saturday's Nebraska game because of "multiple threats," the university athletics website said Thursday night.
A graduate assistant at the time, Mike McQueary told a grand jury he had witnessed former defensive coordinator Jerry Sandusky, now 67, assaulting the boy at the campus football complex.
Questions over how university officials responded to reports of alleged abuse cost coaching legend Paterno and university President Graham Spanier their jobs. McQueary has been criticized for not calling police, but he has not faced any legal charges.
According to a grand jury report, the graduate assistant entered a locker room on a Friday night in 2002 to stow away some sneakers.
"As the graduate student entered the locker room doors, he was surprised to find the lights and showers on," the grand jury report stated. "He then heard rhythmic, slapping sounds."
The assistant looked into the shower and "saw a naked boy ... whose age he estimated to be 10 years old, with his hands up against the wall, being subjected to anal intercourse by a naked Sandusky," the grand jury report stated.
The graduate assistant reported the incident to Paterno, who in turn alerted Athletic Director Timothy Curley, Pennsylvania Attorney General Linda Kelly said earlier this week.
Kelly said the alleged failure of Curley and Gary Schultz, the university's senior vice president for finance and business, to report abuse claims to authorities "likely allowed a child predator to continue to victimize children for many, many years."
Instead of reporting the incident to authorities, Curley and Schultz banned Sandusky from having children from the charity he founded, Second Mile, visit the football building, Kelly said.
Sandusky's lawyer told CNN Thursday evening his client has already been tried in the court of public opinion.
Sandusky, who faces child rape charges, disputes the 23-page grand jury summary of graphic testimony, said attorney Joseph Amendola.
Penn State's new interim head coach carried a blunt message of solidarity for the alleged victims of sex abuse, firm confidence in his embattled players and a paean for Paterno.
Tom Bradley, the longtime defensive coordinator for the team, faced a roomful of relentless reporters Thursday working to glean more details about a case rocking the sports world.
Bradley didn't discuss the investigation, but he said he and his players were thinking about and grieving for the victims of the abuse and their families.
"We all have a responsibility to take care of our children," said Bradley, a Johnstown, Pennsylvania, native who played for the Nittany Lions in the 1970s and has been on the team's coaching staff for 33 seasons.
The university's board of trustees on Wednesday night fired Paterno, the winningest coach in major college football, and Spanier, effective immediately, a bombshell announcement that punctuated the gravity of the scandal.
A beloved national figure for his success on the field and his focus on academics and civics, the 84-year-old Paterno has faced withering criticism over his response to the charges against Sandusky.
Paterno reported the allegations to his boss. Pennsylvania's attorney general said it appeared Paterno had met his obligations under state law, but critics have said the coach should have reported the suspected abuse to police.
That perceived lapse led to the coach's downfall.
State Rep. Kevin Boyle, a Philadelphia Democrat, told CNN's Anderson Cooper he plans to introduce a measure aimed at ensuring that people who witness or learn of the abuse of a child report it to the proper authorities.
"In light of the alleged child sex abuse scandal at Pennsylvania State University, it is clear that a loophole exists in our law," Boyle said in an earlier news release. "My legislation would close that loophole by requiring those who are aware of the abuse to report it to law enforcement authorities, rather than simply following an in-house chain of command."
Boyle told "AC360" there was a deliberate "plot" by Penn State to cover up the allegations against Sandusky.
Bradley wouldn't discuss his relationship with Sandusky, whom he once worked for. But he delivered high praise for Paterno, remarks reflecting the strong love and allegiance people across America have had for the coach.
Paterno had a "dynamic impact" on many, and Bradley said he was "proud" to work for him. He said Paterno has "meant more to me than anybody except my father."
Backers of the coach affectionately known as "JoePa" showed up angry Wednesday night after news of his firing.
Hundreds of Penn State students spilled into the streets of State College in what started as an apparent celebration of Paterno, but it turned into a riot. The crowd tipped over a news van and decried the media in anger over Paterno's departure.
Penn State's Daily Collegian newspaper reported that "thousands of students gathered at Old Main at around 10:30 p.m., chanting "f--- the trustees" and "we want Joe."
"We stand united as students. We don't care what anyone else has to say. We want Joe," the Collegian quoted a student named Jimmy Gallagher as saying.
The newspaper reported that people hurled rocks and lit a small fire. Police moved in to restore order amid dismantled lightposts, broken windows and the smell of gasoline, according to the Collegian.
"Penn State does not need to be put in a worse light than its leaders already have," the Collegian editorialized. "The spotlight was on Penn State last night and we only drew more negative national attention to the Penn State name. The national media did not come for the students, but they stayed because we put on a show. The emotions brought on by the night varied from somber and respectful to angry and unlawful. This is not what Joe would have wanted."
Gov. Tom Corbett decried the violence.
"The eyes of the nation are on you," he reminded residents. "Please behave and demonstrate your pride in Penn State. Your actions speak much louder than your words."
Bradley, noting the disturbances, said he isn't worried about safety on game day.
Nebraska athletic director Tom Osborne said Thursday that while he expects fans of both teams to be respectful, he wants to be sure the environment for the visiting Cornhuskers is secure.
"When you have more than 100,000 people in a stadium, it's probably impossible to conjure up enough officials, security people to absolutely guarantee what's going to happen," Osborne told Lincoln, Nebraska, radio station KLIN. "I just don't know how you do that. We will visit with them today and probably tomorrow and do everything within our power to make sure that there's adequate safety and security provided."
Nebraska's chancellor, Harvey Perlman, also released a statement, and expressed sympathy for the alleged victims in the Sandusky case.
"Looking ahead to Saturday's game, others will pour many issues into this football game," Perlman said in a statement. "Nebraska's participation in no way condones the conduct that has been alleged or makes a statement about the truth or falsity of the allegations."
Speaking to about 15 students gathered outside his house late Wednesday, Paterno said it will take time getting used to his new status after more than 60 years of coaching.
"A tragedy occurred, and we all have to have patience to let the legal process proceed," Paterno said in a written statement. "I appreciate the outpouring of support but want to emphasize that everyone should remain calm and please respect the university, its property and all that we value."
Pennsylvania's U.S. senators, Pat Toomey, a Republican, and Bob Casey, a Democrat, announced that they were rescinding their support for the nomination of Paterno for the Presidential Medal of Freedom.
Sandusky, who was arrested Saturday, is accused of sexual offenses, child endangerment and "corruption of a minor" involving eight boys, most or all of whom he met through The Second Mile, the charity he founded to help troubled youths, prosecutors said.
Sandusky's involvement with The Second Mile provided him with access to "hundreds of boys, many of whom were vulnerable due to their social situations," the grand jury said. The former coach is said to have engaged in fondling, oral and anal sex with boys over at least 15 years, according to the investigative grand jury's summary of testimony.
Sandusky served 23 years as defensive coordinator for the Nittany Lions football team before retiring in 1999. Free on $100,000 bail, he has been accused of sexually abusing boys between 1994 and 2009.
CNN's Dana Garrett, Sarah Hoye, Stephanie Gallman, Ed Payne, Samuel Gardner III, Jason Carroll, Jason Kessler, Laura Dolan and Kiran Khalid contributed to this report.