HARRISBURG, Pa. — A former president of Penn State and two other former university administrators were each sentenced Friday to at least two months in jail for failing to alert authorities to a 2001 allegation against ex-assistant football coach Jerry Sandusky, a decision that enabled the now-convicted serial predator to continue molesting boys.

"Why Mr. Sandusky was allowed to continue to the Penn State facilities is beyond me," Judge John Boccabella said.

"All three ignored the opportunity to put an end to (Sandusky's) crimes when they had a chance to do so," the judge said.

Ex-president Graham Spanier, 68, got a sentence of 4 to 12 months, with the first two to be spent in jail and the rest under house arrest.

Former Penn State president Graham Spanier walks to the Dauphin County Courthouse in Harrisburg, Pa., Monday, March 20, 2017. Matt Rourke / AP

Former university athletic director Tim Curley, 63, received a sentence of 7 to 23 months, with three in jail. Former vice president Gary Schultz, 67, was sentenced to 6 to 23 months, with two months behind bars.

The judge also criticized the actions of the late head football coach, Joe Paterno, who like the other administrators failed to alert child-welfare authorities or police to the 2001 complaint, but was never charged with a crime.

Paterno "could have made that phone call without so much as getting his hands dirty. Why he didn't is beyond me," Boccabella said.

The three former Penn State officials all apologized for their actions and to Sandusky's victims before the sentences were handed down.

"I deeply regret that I did not intervene more forcefully," Spanier said

Curley and Schultz also told the court they were sorry they didn't do more.

"I am very remorseful I did not comprehend the severity of the situation. I sincerely apologize to the victims and to all who were impacted because of my mistake," Curley said.

Penn State athletic director Tim Curley walks out of the Magisterial District Court after being arraigned on charges of perjury and failure to report under Pennsylvania's child protective services law on November 7, 2011 in Harrisburg, Pennsylvania. Patrick Smith / Getty Images file

Said Schultz: "It really sickens me to think I might have played a part in children being hurt. I'm sorry that I didn't do more, and I apologize to the victims."

Prosecutors slammed all three men, saying they cared more about themselves than about protecting children.

They reserved their harshest words for Spanier.

"He was a complete and utter failure as a leader when it mattered most," said Laura Ditka, a state prosecutor.

She said he kept Penn State trustees in the dark about the Sandusky complaint and "he allowed children to be harmed."

The three men were accused of hushing up a 2001 allegation about Sandusky sexually abusing a boy in a football team shower to protect the university's reputation.

As a result, prosecutors said, the retired coach went on to victimize four more boys.

All three men have denied they were told the encounter in the shower was sexual in nature.

Former Penn State vice president Gary Schultz arrives for his sentencing hearing at the Dauphin County Courthouse in Harrisburg, Pa., Friday, June 2, 2017. Matt Rourke / AP

Prosecutors dropped more serious charges against Curley and Schultz as a result of their pleas, and agreed they would not recommend a sentence for them. But in documents filed on the eve of the sentencing, they assailed the two men over their testimony at Spanier's trial.

They suggested that Curley was purposely forgetful, and that it defied common sense that Schultz seemed unwilling to acknowledge the sexual nature of the allegation about Sandusky.

Spanier's trial revolved around testimony by an ex-graduate coaching assistant, Mike McQueary, who said he reported seeing Sandusky molesting a boy in 2001.

Sandusky was not arrested until 2011, after an anonymous email to a county prosecutor led investigators to approach McQueary. Sandusky was found guilty the next year of sexually abusing 10 boys and is serving a prison sentence of 30 to 60 years while he appeals his conviction. At least four victims at Sandusky's trial said they were molested after 2001.

The scandal led to the firing of beloved football coach Joe Paterno shortly after Sandusky's arrest, and he died of cancer two months later at the age of 85.

The Hall of Fame coach was never charged with a crime, but a report commissioned by the university concluded he was part of an effort to keep a lid on the allegations against Sandusky for fear of bad publicity.

Penn State's football program suffered heavy sanctions from the NCAA, and the university has paid out nearly a quarter-billion dollars in fines, court verdicts, settlements and other costs.

McQueary testified about how he went to Paterno a day after the shower encounter to discuss what he had seen. Paterno notified Curley and Schultz, and McQueary met with both of them about a week later. In his 2011 grand jury testimony, Paterno said he was told by McQueary the encounter involved "fondling" and was of "a sexual nature," but wasn't sure what the act was.

The prosecution's key evidence included notes and email exchanges in which Curley, Schultz and Spanier debated what to do after McQueary's report.