Ricardo B. Brazziell AMERICAN-STATESMAN 4/21/11 Cesar Millan, better known as the dog whisperer visits fort hood to check out their dog unit.

Well-known TV personality and dog trainer Cesar Millan is under investigation for possible animal cruelty after a clip from an upcoming episode of his “Dog Whisperer” show was shared online, multiple outlets, including the Los Angles Times, are reporting. In the segment, Millan is working with a dog who reportedly has attacked pigs in the past, and he uses a couple of pigs in the training. At least one pig is bitten by the dog.

National Geographic Wild, which airs the show, released a statement saying viewers were misinterpreting the clip. “The clip caused some concern for viewers who did not see or understand the full context of the encounter,” according to the statement. “The pig that was nipped by Simon (the dog) was tended to immediately afterward, healed quickly and showed no lasting signs of distress.”

A Change.org petition has started, urging National Geographic to take Millan’s show off the air. Millan’s methods have been questioned by other trainers and behaviorists before, including another well-known TV dog trainer, Victoria Stilwell (“It’s Me or the Dog”), who tweeted about the recent incident.

We interviewed Millan before a 2012 appearance in Austin.

Update: Cesar Millan has posted a second clip on his website from the episode about Simon, to “provide missing context.” The post with the clip says,  in part, “Cesar Millan is and will continue to fully cooperate with authorities in ?any investigation. He is confident that the investigation will show there was no wrong doing.”