WASHINGTON >> Midway through a routine Internet search, James Carter IV stumbled upon a video that just didn’t seem right.

The grandson of former President Jimmy Carter and a self-fashioned Democratic opposition researcher, the younger Carter had watched countless hours of footage of Republican Mitt Romney and made it a habit to search YouTube every few days for keywords like "Romney" and "Republicans."

But on this day in August, one clip jumped out. There was Romney, in an undisclosed location, bluntly discussing a visit to a Chinese factory with substandard conditions.

"The hidden camera video — it was all blurred out at the beginning, and it was mysterious," Carter said. "It piqued my interest."

Something told him there might be more there than the brief clip posted on the YouTube channel "Anne Onymous." Although not affiliated with any campaign or super PAC, Carter had made it a personal mission to help get Democrats elected in 2012 — and to do his part to push back against Romney’s relentless campaign-trail mockery of his grandfather.

So Carter, 35, of Atlanta, set out track down the source of the video. He sent a message to the YouTube user seeking details. No luck. But then, after sharing links to the video on Twitter, Carter realized he had a new follower with the same name as the YouTube account. He quickly shot off a direct message.

"They were wary at first," Carter said in an interview with The Associated Press. "But they did respond."

What followed was a delicate, concerted effort to convince the source — still unknown to the public — that Carter could be trusted, and that the world had to see the rest of what was surreptitiously recorded as Romney spoke in May to donors who had paid $50,000 a person to attend the private fundraiser.

In a string of Internet conversations, Carter showed the source evidence that he had helped David Corn, a journalist with the magazine Mother Jones, report a story about Global-Tech Appliances Inc., a Chinese firm that Romney’s Bain Capital briefly invested in. Both Carter and the source suspected it was that firm’s factory that Romney was speaking about in the video.

"That gave me credibility," Carter said. "They opened up to me a little bit."

Soon after, Carter persuaded the source to trust Corn with the full video — on the condition that he keep the source’s identity a secret. Corn ran with it, using clues in the video to triangulate when and where it had been recorded.

Then on Monday and Tuesday, Corn posted the clips to his magazine’s website, sparking a firestorm for the Romney campaign over remarks claiming that nearly half of Americans "believe they are victims" deserving government help and that the Palestinians have no interest in peace with Israel.

"James: This is extraordinary. Congratulations! Papa," the former president told his grandson Tuesday morning in an email obtained by the AP.

For Carter, whose Twitter profile notes he’s looking for work, his success in unearthing the video was followed by a string of job offers Tuesday, from the Ohio Democratic Party to online news sites like The Huffington Post and ThinkProgress.

But the coup de grace for Carter is the irony that Romney has spent many months assailing the elder Carter’s record on everything from foreign affairs to small business policy, hoping to saddle the incumbent president with the less popular vestiges of his Democratic predecessor.

"I’ve gotten a lot of Twitter messages from people supporting me and saying that it’s poetic justice that it was a Carter that uncovered this, considering the way that the Romney campaign has been talking about my grandfather," Carter said. "I agree with that sentiment wholeheartedly."