Kathleen Kane

Pennsylvania Attorney General Kathleen Kane has pledged to conduct a through review of how the Jerry Sandusky case was handled.

(The Associated Press/file)

A spokesman for Gov. Tom Corbett confirmed Friday that Corbett was interviewed this week in connection with Attorney General Kathleen Kane's look back at one of his biggest cases – the Jerry Sandusky child sex abuse scandal.

Aside from confirming that the big interview took place, no comments filled the air from all sides connected to the probe.

But there was one unmistakeable vibe: this likely means that Kane's unusual internal review of a winning prosecution that's withstood all appellate challenges to date is in its closing stages.

One source who's been briefed periodically on aspects of Special Deputy Attorney General Geoff Moulton's work but who asked not to be identified because he is not authorized to speak publicly about the case said Friday he believed Corbett will be the last witness to go in the books.

That makes sense to an outside observer who's also been closely following the longtime Penn State football defensive coordinator's case.

In the typical life cycle of investigations, Duquesne University law professor Wes Oliver noted, a potentially climactic witness is interviewed late for the simple reason that investigators want as much knowledge as possible about the rest of the case to inform their questions.

Since Kane's probe was born of questions she said she'd consistently received on the campaign trail in 2012 about the Sandusky case's management, Corbett - who was sitting Attorney General when the office received the case in 2009 but already eyeing his 2010 gubernatorial run – is about as climactic as they come.

This week's interview, Oliver said, suggests Moulton "has at least taken his first crack at everyone he wants to hear from."

Kane's pledge has been to conduct a thorough review of what became a 33-month Sandusky probe to answer lingering questions like why the former coach wasn't arrested after the first credible witness came forward; why the case was turned over to a grand jury; and whether external factors like Corbett's gubernatorial aspirations influenced its pacing.

"I was on the campaign trail almost two years; I didn't go a single place without somebody asking me why it took so long," Kane told The New York Times in an interview after taking office last January.

Some have theorized that Corbett may have timed the Sandusky probe so it wouldn't break before the 2010 election - given Pennsylvania's long and intense love affair with Penn State football.

Corbett, who is seeking his second term as governor this year, has always denied any political interference in the timing or direction of the Sandusky case, a contention that his former AG staffers have consistently backed up to this point.

They've said their methods, including the use of the grand jury, helped build a stronger case by showing a continuous course of conduct by the beloved Sandusky, and he has noted that process accelerated only after a telephoned tip in late 2010 about the 2001 assault that had been seen by then-Penn State graduate assistant Mike McQueary.

Here is what is known about Moulton's probe so far, according to sources who have been tracking it:

Moulton has spoken to many of the key players who led the investigation.

In her one-year update on the status of the review, Kane also noted that Moulton had obtained access to the office's e-mails from that time period, which would provide a unique, as-it-happened window on the case.

What is less clear is who else is on the witness list.

Moulton's expense records listed his attendance at a national conference last August at which Aaron Fisher, the boy whose 2008 school office breakdown would launch the Sandusky probe, was a keynote speaker.

Other possible witnesses that could be key to understanding the pace of the probe include the judge who supervised the Sandusky grand jury, Barry Feudale.

Feudale was removed from his position last year at Kane's behest.

But unless the review's scope has expanded, it seems less likely that it will go into the prosecutors' inter-actions with former FBI Director Louis Freeh, who wrote the controversial report on university administrators' role in the Sandusky case.

Freeh's group wasn't hired until after Sandusky's November 2011 arrest.

The once-beloved assistant to legendary Penn State football coach Joe Paterno was subsequently convicted in 2012 of sexually abusing 10 different boys between 1994 and 2008.

Sandusky, at age 70, is currently serving a 30-year minimum prison term in western Pennsylvania.

Once Moulton has completed his report, there are two other steps that are supposed to take place before it goes public:

Because the Sandusky case was taken before a grand jury, which operates in secrecy, the current grand jury judge is going to review the findings to make sure those walls haven't been breached.

Kane has pledged to give key participants in the case, perhaps including Corbett and his lead prosecutor, Frank Fina, the ability to review the findings and write a rebuttal before the final release.

With Corbett's interview only going in the books this week, it's unlikely the process has reached those final stages yet.

But it may not be too much longer.