But as Victim 1 grew increasingly uneasy, investigators were carefully building a case against one of the most famous faces in local sports and philanthropic circles.
On Monday, Sandusky's attorney, Joseph Amendola, faces the task of dismantling that case - one that even he conceded, in his opening remarks to jurors, contains "overwhelming evidence" against his client.
But as lead investigator Anthony Sassano explained, it took all of three years to persuade reluctant witnesses to pore through stacks of photos and documents and to secure cooperation from Penn State and Sandusky's charity, the Second Mile, to build a case prosecutors were sure would stick.
The complicated course of the inquiry - outlined last week in trial testimony and interviews with sources familiar with its progress - offers at least a partial answer to one of the most persistent questions to emerge: Why did authorities fail to arrest Sandusky as soon as one credible accuser came forward?
"We had to find more victims," said one source unauthorized to discuss the investigation publicly. "Can you imagine? One kid up against Jerry Sandusky and all of Penn State? Nobody would have believed him."
Since Sandusky's arrest in November, much has been made of the slow pace of the investigation. Gov. Corbett's critics wondered whether he, as attorney general, had ignored evidence of alleged crimes for fear of angering Penn State's considerable fan base on the eve of his gubernatorial election - a charge Corbett has repeatedly denied.
Others theorized that investigators were so eager to find evidence of a Penn State cover-up that they lost sight of the suspected child predator at the center of their case.
And the delay may have put other children at risk. During his testimony Thursday, the 18-year-old identified as Victim 9 told jurors Sandusky continued to orally and anally rape him up until 2009, months after Victim 1 made his first report.
But as soon as investigators began asking questions in spring 2009, it became clear to them the 18-year-old boy who had launched their investigation was unlikely to be Sandusky's only victim.
Internet message boards had roiled for years with rumors about the former coach. Sandusky, who founded the Second Mile to aid underprivileged youth, rarely appeared anywhere without a coterie of children by his side.
Sassano told jurors Thursday the first real break came in 2010 with an anonymous e-mail sent to Centre County District Attorney Stacy Parks Miller.
You want to know about Sandusky, it read, talk to Mike McQueary.
Then an assistant coach with the university football program, McQueary more recently famously told investigators that nine years earlier, while still a graduate assistant, he had walked in on Sandusky sodomizing a boy in a locker-room shower.
But when detectives arrived on his doorstep in late 2010, the young coach was reluctant to talk.
McQueary explained in testimony Tuesday that his previous attempts to notify university higher-ups - head football coach Joe Paterno, athletic director Tim Curley, and the university vice president in charge of police, Gary Schultz - had gone nowhere. He wondered what would be different if he tried again.
McQueary ultimately agreed to testify. But his story changed the course of the investigation.
No longer was the case solely about an alleged pedophile operating in secret, Sassano said. It now appeared that top university officials may have known about Sandusky's alleged crimes for years.
That suspicion led investigators to a 1998 report buried in the Penn State police department's archives outlining a previous complaint.
The case involved allegations that Sandusky inappropriately touched an 11-year-old in a locker-room shower. Its 100-page file contained damning details, like Sandusky's admission to showering with other boys and his lament to the child's mother - overheard by detectives - that he understood he was wrong and wished he were dead.
Centre County authorities had declined to prosecute the case at the time, perhaps because, as alleged victims go, the child at its center was not exactly an ideal witness.
Now a young man identified as Victim 6, he testified last week that in 1998, he did not feel he had been victimized at all. "It wasn't a big deal to me," he said.
Sassano and his colleagues kept digging.
"We were thinking both of these incidents occurred at night," he said. "Who else would be around at night?"
That led them to Ronald Petrosky and Jay Witherite, two janitors who recalled a coworker claiming in 2000 to have seen Sandusky engaged in oral sex with another boy.
But that man, Sassano found, had succumbed to dementia and was unable to remember the alleged incident.
So, despite the promising leads investigators had amassed by 2010, with only one alleged victim, an eyewitness who couldn't testify, and an assistant coach who never reported what he saw directly to police, prosecutors felt their case still remained too weak to put before a jury.
They launched a concerted effort to find more alleged victims.
Detectives obtained lists of former Second Mile campers, contacted all who still lived within an hour's drive of State College, and pored over the photographs in Sandusky's 2001 autobiography, hoping they could identify the boys pictured within.
But as investigators fanned out across the state, they found even the boys they were most certain Sandusky had abused were reluctant to talk. Among them was the 28-year-old now known as Victim 4.
Sassano encountered photos of the child nearly everywhere he looked - in Sandusky's book, in a write-up on the Second Mile in Sports Illustrated, and in football videos the former coach produced in the late '90s.
Penn State travel records showed that this boy had accompanied Sandusky to bowl games. And former coaches and players recalled him as a constant presence at the coach's side.
But when investigators approached him, Victim 4 turned them away.
"I don't even really want to be involved now," he told jurors last week.
Eventually, though, he was persuaded to cooperate. He helped lead them to others, who later became accusers.
Using a photograph of himself, Sandusky, and seven other boys, Victim 4 identified four young men, all of whom took the stand last week. At the time, though, he was unaware that they would allege abuse.
Most had to be coerced by grand jury subpoenas to testify, Sassano said.
"It was a daunting task to get them to come forward," he told jurors Thursday. "I wouldn't want to sit here and discuss with you my sexual experiences, either."
In his testimony Monday, Victim 4 credited investigators' three years of work building a case impossible to discount out of hand with finally persuading him it was safe to break his silence.
And, as Sandusky's trial enters its second act Monday, he and seven others will learn whether those efforts were enough.
Contact Jeremy Roebuck at 267-564-5218 or firstname.lastname@example.org.
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