Bradley Manning's Father Says His Greatest Fear Is Son Is Guilty

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WATCH Is Pvt. Bradley Manning Behind Leak?

When people ask Brian Manning if he is related to Pvt. Bradley Manning, he sometimes denies it. The thought that his son could be guilty of leaking classified information to WikiLeaks -- including Afghan and Iraq war logs, a quarter of a million State Department cables and two videos -- scares the elder Manning.

He hasn't had a chance to ask his son, who was arrested in May 2010, if he's guilty -- but if he is, Brian Manning was matter-of-fact in what he'd say to his son.

"You f---ing stupid idiot. Why would you do something like that?"

He added, "I would be openly embarrassed at holding up thinking he's innocent and I'd be embarrassed he'd done such a thing."

But for now, Brian Manning, who was a naval intelligence officer during the Vietnam War, is sticking by his son and denying reports the two had a fractured relationship.

Many Americans know little about the soldier accused of leaking the mountain of military secrets to WikiLeaks beyond his name and now-recognizable picture.

"He was always very energetic. He was just a pretty normal kid," his father said of the 23-year-old who now sits in a cell at Fort Leavenworth, awaiting a military trial on charges that could keep him locked up for the rest of his life.

A recent PBS "Frontline" documentary obtained Bradley Manning's Facebook page, where he wrote openly about being gay, opposing the military's "don't ask, don't tell" policy and the feelings of loneliness and isolation he experienced in the army.

In fact, they were feelings so acute that Manning's superiors almost didn't send him to Iraq because he was considered emotionally unstable. Somehow the young private ended up working in a top-secret facility -- a place where he would have access to classified documents.

"The only other reason I could see him doing this is being cocky and tech savvy and 'I can get all this crap and send it out to WikiLeaks and brag on a text to somebody else,'" Brian Manning said.

Bradley Manning was arrested in May 2010 after allegedly bragging to a hacker about leaking a trove of documents to WikiLeaks.

For all those who hail his son as a whistle-blowing hero, Manning said he simply doesn't buy it.

Even though he's sticking up for Bradley now, Brian Manning knows there are even more twists and turns ahead as his son awaits trial and the potential of spending the rest of his young life in prison.

And for whoever leaked the documents -- even if it was his Bradley -- Brian Manning said he hopes justice prevails.

"Anyone who breaks the law should get what they're entitled to get," he said.