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A local prosecutor in North Carolina is investigating allegations of animal cruelty by a pig farm supplying Smithfield Foods, the nation’s largest pork producer. The investigation comes after an animal rights activist secretly videotaped workers beating and dragging swine, gouging out their eyes and cutting out their testicles.

Attorneys from People for the Ethical Treatment of Animals presented their case to the Sampson County District Attorney's Office in North Carolina on Monday and will turn over videotapes and a signed affidavit by PETA's undercover investigator, who says he witnessed daily violent mistreatment of baby and adult pigs at Murphy Family Ventures Garland Sow Farm in Garland, N.C.

In the black-and-white video, a supervisor can be heard bragging to the undercover PETA investigator that he brutally beats the animals.

Click here to see the video. WARNING: GRAPHIC CONTENT AND EXTREMELY FOUL LANGUAGE.

"I ain't going to lie to you; I've done it," he says. "My temper is about that long. I get f— frustrated and I have knocked the s— out of them. Like that one bit me the other morning, that mother f—.... I cut the s— out of his G—d— nose with a f— gate rod."

In other segments, pigs who have the word "KILL" spray-painted on their backs screech in apparent pain as they're dragged to slaughter with a heavy metal prodder attached to their legs, ears and snouts, and women laugh as they castrate one piglet after another without anesthesia or painkillers.

"One female employee told me that was her stress relief for the week," said the PETA investigator, who spoke to FOXNews.com on condition of anonymity. "That's the type of person doing those jobs. ... The treatment of the baby pigs shook me the most."

He said he also witnessed piglets' tails being sliced off and other atrocities. Castration and tail-chopping are general practice at swine slaughterhouses, according to PETA.

"We believe that these acts of abuse constitute a violation of state animal cruelty laws," said PETA spokesman Matt Prescott. "Employees were gouging out the eyes of pigs and violently dragging animals by an ear or a snout or a leg. A supervisor admitted on camera to viciously attacking pigs with metal rods."

The county said it plans to look deeper into the case.

"I have requested that the State Bureau of Investigation investigate allegations that some employees at a sow farm in Garland, N.C., have abused animals," said Sampson County District Attorney G. Dewey Hudson in a statement. "The request was made as a result of information provided by PETA. As soon as an investigation is completed I will make a decision about whether charges should be filed and will make my decision public at that time."

Murphy Family Ventures pig-breeding farms and slaughterhouses are under contract with Smithfield Foods as pork suppliers. The PETA employee who videotaped the alleged pig abuse said he was hired as an entry-level "herd technician 1" and worked from Sept. 13 until Nov. 2 of this year.

"[The abuse of pigs] happened every day," said the PETA investigator. "The video is compelling to people, but it pales in comparison to seeing it every day in person. You can't even capture the full horror of what goes on there."

PETA wants all those workers it filmed reportedly abusing the pigs charged with animal cruelty, a criminal offense that's generally classified as a misdemeanor under North Carolina law.

It also is demanding that Smithfield Foods become more proactive in enforcing its animal welfare program by adopting measures including installing surveillance cameras at its farms and slaughterhouses and conducting its own internal investigations into how operations are handled.

Smithfield's livestock subsidiary Murphy-Brown LLC, which is a different company from the contracting farm Murphy Family Ventures, said it is doing its own probe into the accusations of abuse at its slaughterhouses.

"An investigation into the allegations of animal abuse at the Garland sow farm has begun," the company said in a statement. "When the investigation is completed we will take the appropriate actions if violations of the company's animal welfare policy are identified."

The corporation said that the alleged cruelty occurred not on a company-owned or operated farm but on one contracted by Smithfield and Murphy-Brown, and vowed to work with the farm to make sure it was adhering to corporate standards for animal care.

Corrective action would be taken if the slaughterhouse is found to be violating those guidelines, according to Murphy-Brown.

The 2,200-pig farm that has come under fire said that it, too, is looking into the situation.

"We have received information about this matter and are reviewing these specific allegations," said Murphy Family Ventures in a statement. "The company is conducting its own internal investigation to determine the facts in this matter and will take any appropriate actions necessary. As a first step, farm managers were directed to fully review our animal welfare policies and practices with all farm staff immediately."

The farm and slaughterhouse also said it will "aggressively mandate strict compliance" with Murphy-Brown's animal welfare practices and will fire anyone caught violating it.

"The policy states that 'Willful neglect or abuse of animals will not be tolerated and will result in immediate termination,'" Murphy Family Ventures said. "Any person or persons involved with abuse will be subject to the policy."

The investigator said he quit the $7-an-hour job with a week's notice because he feared his coworkers had begun to suspect him, since he said he was the only one who wasn't physically harming the pigs on the farm.

"I was the only person there not abusing the hogs," he said. "Everybody there — my supervisors, managers — commented to me that you have to hit them to make them move. I do think they suspected me because I never once would do that. That definitely made me stand out. I don't think they look at them like animals. They look at them like a piece of merchandise."

PETA says it conducted the undercover probe after receiving a tip in August from a former Murphy Family Ventures employee who reported similar animal cruelty on another of its farms. The PETA investigator said he couldn't get a job there but was hired to work at the Garland location, where he said he witnessed the abuses.

The North Carolina State Attorney General's office said it won't get involved in the case unless requested to do so by Sampson County authorities. To date, said state Attorney General spokeswoman Noelle Talley, the local D.A. hasn't approached her office for help.

The U.S. Department of Justice declined to say whether it planned to open a federal probe into the case.

"We don't have any comment on the local district attorney's investigation," said DOJ spokesman Andrew Ames in an e-mail to FOXNews.com.

Smithfield has come under scrutiny before for human rights violations, hiring of illegal workers and labor union practices.