Sandusky has not been charged. A grand jury examines accusations to determine if evidence warrants filing charges.
A message left by The Associated Press at a number listed for Sandusky in State College was not immediately returned. An employee for his attorney, Joseph Amendola, said Amendola was out of the office Thursday.
The Patriot-News in Harrisburg reported Thursday that it spoke to five anonymous sources with knowledge of the case who say a grand jury has been meeting in Harrisburg for 18 months to hear allegations made by a 15-year-old boy in 2009.
The paper reported the teen told authorities that there was inappropriate contact over a four-year period.
Sandusky retired after the 1999 season after 32 years as an assistant to Penn State football coach Joe Paterno. Once considered a potential successor to Paterno, Sandusky helped establish Penn State's "Linebacker U" reputation and drew up the defenses for the Nittany Lions' national-title teams in 1982 and 1986.
Sandusky, 67, also has been lauded for his work with The Second Mile, a charitable organization he founded in 1977 to help at-risk children.
He retired from the board of the charity in September, and executive vice president Katherine Genovese said then that he had been dialing back duties in recent years and was looking to spend more time with family and deal with his personal life.
Paterno and Penn State athletic director Tim Curley were among those who appeared before the grand jury in January, the Patriot-News reported.
A spokesman for the athletic department declined to comment Thursday on behalf of athletics and Paterno. Lisa Powers, a spokeswoman for the university, also declined to comment.
The allegations surfaced in 2009 while Sandusky was a volunteer assistant high school football coach at Central Mountain High School in Clinton County, the Patriot-News reported. John DiNunzio, interim superintendent of the Keystone Central School District at the time, said the boy's mother reported an incident to the principal and head football coach.
According to the newspaper, DiNunzio, now interim superintendent at the Bellefonte school district, was told by the coach and principal that the boy alleged contact occurred while he and Sandusky were alone in the room on wrestling mats.
The report was passed on to Clinton County Children and Youth Services. The newspaper, citing anonymous sources, reported the boy told that department that there had been indecent contact several times over four years.
The case was forwarded to the Clinton County district attorney, who then forwarded it to his then-counterpart in Centre County, Michael Madeira, because the incidents where alleged to have taken place in Centre County. Madeira then referred the case to then-Attorney General Tom Corbett's office in March.
DiNunzio told the Patriot-News he never heard from police "once it left his desk." Kelly Hastings, current superintendent of Keystone Central School District, told the newspaper said she has direct knowledge of the report and that documents from the school have not been subpoenaed.
The newspaper also reported that state police in Centre County two months ago began calling witnesses to a May 1998 report by Penn State police detailing an earlier allegation of inappropriate contact against Sandusky by another boy. No charges were ever filed against Sandusky.
In a separate story Thursday, Patriot-News editor David Newhouse said the newspaper contacted the attorney general's office with details of the story, to ask if the newspaper was wrong and to ask if their report would harm the investigation. Newhouse said the newspaper would not have reported the story if it were told "yes," and that the attorney general's office declined to speak with the paper.
Newhouse wrote that, in response to a question from one of Sandusky's friends, the paper would report with equal veracity if charges are never brought and the inquiry dismissed.
"We would owe that to Coach Sandusky, Penn State, The Second Mile and all who have admired his life and work," Newhouse wrote. Responding to the Patriot-News story, Second Mile president Jack Raykovitz said in a statement the organization was "shaken by the article."
"While The Second Mile is referenced in the Patriot News article, we have been advised that neither The Second Mile nor our programs are the subject of any investigation," Raykovitz said. "Out of respect for all parties, we cannot discuss, speculate, or comment further."
Raykovitz said the organization was committed "first and foremost to the safety and well-being of the children we serve. We have zero tolerance for abuse. ... Throughout our history, there have never been allegations made with regard to misconduct occurring during any Second Mile program."