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DEVELOPING: Penn State head football coach Joe Paterno has decided to retire at the end of the season, a source close to the matter told the Associated Press.

The reported decision comes amid a widening child sex abuse scandal and alleged cover-up centered on Paterno's former defensive coordinator, Jerry Sandusky.

The source, who spoke to the AP on condition of anonymity because the decision has yet to be announced, said the 84-year-old Paterno will announce his retirement later Wednesday.

Paterno has been besieged by criticism since Sandusky was charged over the weekend with molesting eight young boys between 1994 and 2009. Athletic director Tim Curley and vice president Gary Schultz have been charged with failing to notify authorities after an eyewitness reported a 2002 assault.

Though Paterno is not accused of any wrongdoing, he has been questioned over his apparent failure to follow up on a report of the 2002 incident, in which Sandusky allegedly sodomized a 10-year-old boy in the showers at the team's football complex. A witness, Mike McQueary, is currently receivers coach for the team but was a graduate assistant at the time.

McQueary told Paterno about the incident the next day, and the coach notified Curley and Schultz, who in turn notified Penn State president Graham Spanier. Curley and Schultz have been charged with perjury and failure to report the incident to authorities, as required by state law.

Both men, as well as Paterno, testified that they were told that Sandusky behaved inappropriately in that 2002 incident, but not to the extent of McQueary's graphic account to a state grand jury.

The Penn State Board of Trustees said Tuesday night it was launching an investigation into the scandal. The board released a statement saying it would appoint a special committee at its regular meeting Friday to "undertake a full and complete investigation of the circumstances that gave rise to the grand jury report" and promised to take swift action.

"The Board of Trustees of the Pennsylvania State University is outraged by the horrifying details contained in the grand jury report," the strongly worded statement read.

"We cannot begin to express the combination of sorrow and anger that we feel about the allegations surrounding Jerry Sandusky.

"Penn State has always strived for honesty, integrity and the highest moral standards in all of its programs. We will not tolerate any violation of these principles."

Paterno's regularly scheduled news conference was abruptly canceled Tuesday by a university spokesman who cited "ongoing legal circumstances."

Hundreds of fans staged a raucous rally outside Paterno's home Tuesday evening. He appeared briefly, along with some family members, and thanked the crowd for coming.

"I've lived for this place. I've lived for people like you guys and girls," Paterno said.

"It's hard for me to say how much this means," the coach said.

"As you know, the kids that were the victims, I think we ought to say a prayer for them."

Asked if he was still the coach, Paterno didn't answer but a young woman who stood with her arm around him replied: "Now is not the time."

Paterno's son, Scott, said his father was disappointed over the decision by PSU President Graham Spanier to cancel the news conference. Addressing reporters outside his parents' house, Scott said Joe was prepared to answer questions about Sandusky -- who maintains he is innocent -- and further that his father plans to coach not only Saturday's game against Nebraska, but for the long haul.

Earlier in the day, Paterno stepped out of a silver sedan being driven by his wife, Sue, and headed to the team practice. At one corner of the facility, managers hastily put plywood boards over an exposed fence to block photographers' view of the field.

At the spontaneous rally at his house, Paterno held his fists over his head three times and said, "We are ..."And the crowd replied, "Penn State!"

"We're always going to be Penn State," Paterno said. "I'm proud of you. I've always been proud of you. Beat Nebraska."

Paterno, who earns about $1 million annually from the school, has been head coach for 46 years and part of the Penn State staff for more than six decades, and his old-school values pervade every corner of the program.

Over that span, the Nittany Lions won two national championships, but unlike many other Division I powerhouses, the program avoided run-ins with the NCAA. The team generates millions of dollars each year in revenues from attendance, TV rights and sponsorships, but it has stubbornly stuck with the basic white-and-blue uniforms that are now among the most recognizable in college football.

All those things have inspired pride in the region and fierce loyalty to Paterno, who is the winningest coach in Division I and one of the most respected in any sport. That lofty status, however, has been the subject of heated arguments in recent days, among students on campus, construction workers on the street and the PSU board of trustees.

A person familiar with the trustees' discussions said support there for Paterno was "eroding," but couldn't gauge whether the board would take action. The same person said Spanier has also lost support ahead of Friday's board meeting, which Gov. Tom Corbett said he plans to attend. The person spoke on condition of anonymity because of the sensitivity of the subject.

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MyFoxPhilly.com's slideshow of rally outside Paterno's home.

Newscore and the Associated Press contributed to this report.