Former Penn State Coach Prosecutor Center of Missing Man Mystery Prosecutor who investigated Sandusky in 1998 went missing in 2005.

Nov. 8, 2011  -- The prosecutor who decided to not pursue sex abuse charges against former Penn State football coach Jerry Sandusky more than a decade ago, despite an alleged confession, is at the center of a missing persons mystery that has enraptured middle Pennsylvania for years.

Ray Gricar served as the district attorney for Pennsylvania's Centre County in 1998 when Sandusky was accused of sexually abusing several boys. After an extensive investigation, which included testimony by two law enforcement officers that they had overheard Sandusky admitting to showering with multiple young boys, Gricar decided no criminal charges would be filed, according to recent court documents. Sandusky retired the next year.

READ: Ex-Penn State Coach Won't Speak on Child Sex Abuse Charges

Then, in April 2005, Gricar disappeared.

His car was found abandoned in a Lewisburg, Pa., parking lot and his laptop's harddrive was recovered from the nearby Susquehannna River, but there was no other trace of Gricar. No clues could be gleaned from the severely damaged harddrive and despite a six year investigation that involved the FBI and international help, police have as little an idea today about what happened to the former DA as they did then.

"We literally used every single resource, national and international," Bellefonte, Pa., police chief Shawn Weaver told ABC News today. "This is baffling. He literally just disappeared off the face of the earth."

READ: Penn State's Joe Paterno Cancels News Conference

In July this year, Gricar was officially declared dead, though Weaver said the investigation into his disappearance is ongoing and new leads continue to emerge.

Weaver said that though everyone has a personal theory about what may have happened to Gricar -- from suicide to foul play -- there has been no evidence to support any one of them. The idea that the disappearance could be linked to the Sandusky investigation, Weaver said, is "highly doubtful."

"Obviously if something raises an eye, it's something we'll look at," he said. "Nothing is out of the realm of possibility."

Robert Buehner, the district attorney for nearby Montour County and longtime friend of Gricar's, told ABC News he's convinced Gricar was murdered but said there was "absolutely" no connection to the Sandusky case. Buehner said Gricar was more likely the target of a violent criminal he had prosecuted or was in the midst of prosecuting. He doubted Gricar would have committed suicide or simply ran off because he was happy, financially stable and often talked fondly of his impending retirement.

As to why Gricar did not pursue charges against Sandusky in 1998, Buehner said that Gricar must simply not have had the evidence he needed.

"If you're going to target someone, you really work very hard to be sure you have a case because if you don't, you could end up ruining someone's reputation and livelihood," Buehner said. "If he had the evidence, Ray would not have concerned himself with who the person was."

Sandusky, a former defensive coordinator for the Penn State Nittany Lions, was arrested Saturday and arraigned on 40 criminal counts connected to the alleged sexual abuse of eight boys over a fifteen year period.

Sandusky declined to comment on the accusations to ABC News Monday.

TIMELINE: Key Dates in the Penn State Sex Abuse Case

ABC News' T.J. Winick and Alyssa Newcomb contributed to this report.