Cesar Millan
Dog trainer Cesar Millan poses with Lassie at 2008 Primetime Creative Arts Awards in Los Angeles September 13, 2008.Reuters

"Dog Whisperer" Cesar Millan is currently being investigated for possible animal cruelty.

A complaint was lodged against the dog behaviourist after a recent episode of "Cesar 911″, which airs on National Geographic, showed a dog named Simon nipping a pig's ear during a training session. According to reports, the complaint was filed by a single citizen whose identity has not been revealed.

"There was a complaint that we received and we are investigating the matter," Deputy Director Danny Ubario of LA County Animal Control told TheWrap Thursday. "An officer visited the centre today and it is currently under investigation."

Besides the complaint, an online petition started on Change.org has more than 8,500 supporters seeking cancellation of the show. Calling Millan's methods "inhumane," a statement on the website pointed out he used the pig as a bait "for a dog who was a known pig killer and all for 'entertainment' purposes."

Another petition with nearly 10,000 supporters wants Millan banned from television.

In a statement to the media, a representative from National Geographic said the pig attacked was tended to immediately and showed no signs of distress. An additional clip released by the channel even showed Simon being taken for a walk by the same pig.

"It is important to clarify that Cesar took precautions, such as putting Simon on a long lead to assess his behaviour, making initial corrections and removing the leash. The pig that was nipped by Simon was tended to immediately afterward, healed quickly and showed no lasting signs of distress," the statement read, adding Millan and his pack of animals helped Simon control his aggression.