The report, commissioned by Attorney General Kathleen Kane and written by former federal prosecutor Geoff Moulton, blamed a three-year lapse in filing charges on communication problems, an expungement of a 1998 complaint about Sandusky and a failure to take certain investigative steps early on.
"The facts show an inexcusable lack of urgency in charging and stopping a serial sexual predator," said Kane, a Democrat who had vowed to conduct a review of the investigation while running for office. "The report documents that more investigative work took place in just one month in 2011 than in all of either 2009 or 2010."
Then-Attorney General Tom Corbett, a Republican, was in the midst of his successful 2010 gubernatorial campaign during the Sandusky investigation.
Moulton said his review "revealed no direct evidence that electoral politics influenced any important decision made in the Sandusky investigation."
As a candidate in 2012, Kane said Corbett may have had a political motive to slow down the investigation, an assertion Corbett denied. Sandusky's arrest led to the firing of longtime Penn State coach Joe Paterno while Corbett was serving as a university trustee.
"This investigation was never about politics," Corbett said in a statement Monday. "It was always about the people victimized by this man."
Sandusky was convicted in 2012 of sexually abusing 10 boys and is serving decades in prison.
At a news conference, Kane said her office knows of two young men who said they were victimized in the fall of 2009, after the attorney general took the case. But the lead prosecutors at trial disputed that claim, which was not part of Moulton's report.
"It is completely false," said Frank Fina, now with the Philadelphia district attorney's office.
One of those who took the stand against Sandusky, known in court as Victim 9, said his contact with Sandusky ended in 2008 or 2009, but Kane said she was not talking about any of the eight young men who testified.
Kane spokesman J.J. Abbott said later the office would not provide additional details.
"Attorney General Kane stands strongly by her statement," Abbott said. "This office is aware of two people who allege abuse into the fall of 2009."
As for the time it took to bring charges, the report said the lead prosecutor at the time, Jonelle Eshbach, hectored her bosses about the case during a stretch in 2010 when the probe was largely dormant.
Eshbach drafted a grand jury report in March 2010 based on the claims of a lone victim, but she spent much of the ensuing months — as Corbett won the primary — trying to get approval for the report.
"In the interim, no witnesses were interviewed, no witnesses testified in the grand jury and no grand jury subpoenas were issued," Moulton wrote. He said the basis for that decision was that one accuser's testimony wouldn't be enough to convict Sandusky and an acquittal would make it harder to file more charges later.
Fina told reporters Eshbach agreed with others that the case would not succeed with just one victim.
Her lawyer disputed that.
"If that was true, why would her supervisors ask her to revise the (grand jury report) twice? Why would she repeatedly ask for permission from her supervisors to charge?" said her attorney, Ed Paskey.
The report said the investigation picked up steam two days after Corbett was elected governor in November 2010, when the Centre County prosecutor received an anonymous tip directing investigators to assistant football coach Mike McQueary, whose testimony eventually helped convict Sandusky.
Additional victims were identified, and on June 21, 2011, Sandusky's home was searched, producing photos and typewritten lists of children who participated in events at Sandusky's charity, The Second Mile, with some names highlighted.
According to the report, prosecutors told Moulton they waited until 2011 to search Sandusky's home computer and subpoena child protective services records because they "believed that they were unlikely to be productive and would have risked publicly revealing the existence of the investigation."
More resources early on, including additional investigators, may not have speeded up the case, Moulton said, because the best leads were not related to how many detectives were devoted to the matter.
He said decisions not to bring charges based solely on one accuser or, in June 2011, after three more witnesses had testified before a grand jury, "fit within acceptable bounds of prosecutorial discretion."
Moulton noted that if authorities had put together a larger team early on, it's possible someone may have known about or turned up a 1998 police investigation of Sandusky prompted by a mother's complaint that the coach had showered with her son.
Also Monday, a state hearing examiner recommended that Sandusky's $4,900-a-month pension be reinstated and he receive payments back to October 2012, when his benefits were cancelled. A final decision by the State Employees' Retirement Board could occur this fall.