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An amateur cameraman claims he's got video proof that California Sen. Barbara Boxer's supporters enlisted day laborers to hold signs protesting her Republican opponent.

Derek Broes, a supporter of GOP Senate nominee Carly Fiorina, has released a video he shot outside a Pasadena debate that showed two Spanish-speaking men holding a slapdash white sign accusing "corporate cash" of loving the Republican candidate.

Though the audio is hard to hear, one of the men clearly says he did not make the sign -- another appears to say a "lady" was paying them to hold it. The men do nothing to suggest they are day laborers, but Broes told FoxNews.com he saw them at a well-known day laborer site at the nearby U-Haul just moments before. He said the men were expecting to be paid, though they may have gotten "stiffed," and that the signs came from what appeared to be a Boxer campaign truck.

"These people don't even know what they're protesting and they're being asked to hold signs," Broes said. "It's a manufactured protest."

The Boxer campaign insists it had nothing to do with the scene. The campaign said it does not pay or offer to pay anybody to hold signs and nobody interviewed in the amateur video was with the Boxer campaign.

"There were dozens of volunteers who came out to support Barbara Boxer at the debate, but absolutely no one received any payment from the Boxer campaign and any assertion that they did is simply false," campaign manager Rose Kapolczynski said in a written statement.

The identities of the people in the video are somewhat of a mystery. The Boxer campaign said it has no idea who the men carrying the sign were. The Pasadena Star-News tracked down one individual who said, without giving his name, that he was in the video and that "some of the guys thought they might make some money by holding the signs, but they were never paid."

Then there's the woman who allegedly offered to pay the workers. The unidentified woman claimed responsibility for the sign in the video and later told Broes, "We should have brought more (signs)" when informed that the guys were looking for more banners to hold.

She could also be heard saying: "It came up so quickly, there wasn't a whole lot of time to get people together."

Broes said the lady appeared to be with the Boxer campaign, considering she showed up when an official-looking truck arrived with the campaign signs.

But the Boxer campaign aide said nobody on staff recognized the woman or the people she was with. "They were not ours," the aide said.

The Fiorina campaign could not confirm the claims but said the scenario points to potential problems in Boxer's base.

"If these allegations are true it is disappointing. If Barbara Boxer had to pay people to protest on her behalf it is a clear sign that the enthusiasm gap is wider than we thought and a sure sign that the people of California have had enough of her 28 years of out of touch failed policies," the Fiorina campaign said in a statement.

Broes, a former Microsoft executive who worked with Fiorina when she was heading up Hewlett-Packard, said he wasn't planning to shoot video of the Boxer activity when he first showed up at the debate site -- ironically, that debate focused in part on immigration and outsourcing. Broes said he was just carrying a camera to shoot generic footage and decided to videotape when he saw the men from the U-Haul site.

He said the men disappeared, along with the signs, shortly after he started shooting video and asking questions.

"Apparently they thought they were going to get paid," he said. "They're not volunteering their time out there standing in the hot sun."