Jerry Sandusky's behavior exhibited a "pedophile's pattern of building trust," a psychologist told police in 1998 after interviewing one of the former Pennsylvania State University assistant football coach's alleged victims.

But after evaluating the same boy, another expert concluded that Sandusky had done nothing that could not be "defined as normal between a healthy adult and a young adolescent male."

Those conflicting analyses - both included in a police report that year on allegations that Sandusky had touched an 11-year-old inappropriately in a locker-room shower on the Penn State campus - suggest a possible answer to one of the central questions to emerge since the former coach's arrest last year on more than 50 counts of child sex abuse.

Why didn't authorities act 14 years ago when accusations against Sandusky first surfaced? At the time, the evidence was inconclusive, according to the police file obtained first by NBC News and then by The Inquirer and several other media outlets Saturday.

"As a result of the investigation, it could not be determined that a sexual assault occurred," the report reads.

Asked about the state's case against Sandusky, psychologist Alycia A. Chambers, author of the more damning 1998 analysis, told NBC: "I was horrified to know that there were so many other innocent boys who had been subject to this - who had their hearts and minds abused, their bodies violated. It's unspeakable."

After reviewing the report Saturday, Howard Janet, a lawyer now representing Chambers' former patient, criticized the university for its inaction.

"Penn State University police had in their possession a report from a licensed clinical psychologist that Jerry Sandusky fit the profile of a pedophile," he said in an e-mail. "Did the university take action to ensure Sandusky wasn't endangering children? No, it did not."

University officials declined to comment.

The 1998 investigation and the boy at its center have become a central focus in the case against Sandusky, who has since denied charges that he sexually abused 10 boys over 15 years.

The probe by State College and Penn State police resulted from the first known complaint to authorities involving the former coach and the first time university employees were notified of Sandusky's purported behavior.

According to the grand jury presentment unsealed last year, the boy - identified in the current state case as "Victim 6" - met Sandusky through the Second Mile, a charity he founded for underprivileged youth, and was often invited to Penn State football games.

In May 1998, Sandusky invited the boy to work out with him alone in the campus' football facilities. Once they were done, prosecutors allege, the coach took him into the showers, lathered him up, and bear-hugged him naked from behind.

Later, the boy's mother contacted police, who eavesdropped on a conversation between her and Sandusky. According to the grand jury, he acknowledged showering with her son was a mistake, asked for her forgiveness, and cried out, "I wish I were dead."

In its report last year, the grand jury quoted testimony from the woman's son, now 25.

"Looking back on it as an adult, Victim 6 says Sandusky's behavior towards him as an 11-year-old was very inappropriate," the panel wrote.

At the time, though, the facts were not so cut-and-dry, said Jerry Lauro, a state Department of Public Welfare investigator involved in the 1998 investigation.

The police report obtained Saturday suggests the boy may have been much more ambivalent about the encounter 14 years ago.

"Allegations are one thing," Lauro said Saturday. "Making a founded case is another thing."

He told police and psychologists that Sandusky had not pressured him, the report states. He described horsing around with the coach in the shower as "fun" and recalled laughing.

"He said he did not want Mr. Sandusky to be in trouble," one psychologist's report reads. "He was feeling 'like the luckiest kid in the world' to get to sit on the sidelines at Penn State football."

Some of the document's previously undisclosed details are troubling. Sandusky at one point that day allegedly kissed the boy on the head and said, "I love you."

The former coach also purportedly invited the boy over to his house to "sit on his lap" and use his computer.

Chambers, a psychologist who had been treating the boy since before his days at the Second Mile, evaluated him the day after his shower with Sandusky.

She ultimately concluded that the football games, the computer invitation, and the shower indicated "a typical pedophile overture."

Five days later, Centre County Children and Youth investigators requested a second opinion from John Seasock, a psychologist in nearby Kingston whose practice typically handles adult sex offenders.

Where Chambers saw child abuse, Seasock saw only routine behavior for a coach, who had likely spent years showering alongside his athletes.

"Mr. Sandusky followed through with patterning that he has probably done without thought for many years," Seasock wrote. He later told police he had never "heard of a 52-year-old becoming a pedophile."

The police report suggests that investigators were skeptical of Seasock's conclusions. Asked whether the boy had mentioned the more troubling details alleged in Chambers' report - the kiss on the forehead, the purported offer to sit on Sandusky's lap - Seasock said the child had not.

"Seasock advised that there were still some 'gray' areas," the report reads.

Still, police concluded as he did - that "it could not be determined that sexual assault had occurred." Centre County prosecutors declined the case and ended the investigation.

Neither Chambers nor Seasock could be reached for comment Saturday.

Sandusky's attorney, Joseph Amendola, questioned the timing of the report's release. He has challenged prosecutors in court for refusing him access to either psychologist's findings as he prepares for his client's May trial.

"To date, the attorney general has provided us with only a small fraction of that police report," he said. "We are now left to speculate on what other critical information they have failed to provide the defense team."

The Attorney General's Office did not respond to requests for comment.

Lauro, the DPW investigator, said he never knew about the psychologists' reports when he advised his department to close its case more than a decade ago.

Had he seen them, he "would have made a different decision," he said Saturday. "The course of history could have been changed."

Contact Jeremy Roebuck

at 267-564-5218 or jroebuck@phillynews.com, or follow on Twitter @jeremyrroebuck.