In a lawsuit earlier this month, a gymnast named Lidia Matiss alleged in 2017 that she went to visit her mom, who worked for Millan, at his training facility. She claims at the facility she was attacked by the Dog Whisperer star's late pet Junior, according to TMZ, who obtained a copy of the legal documents.
Junior, the tv star's pit bull, died this year at 15 years of age.
"This incident occurred over 4 years ago. Two weeks ago, Ms. Mattiss' counsel sent a letter demanding that Mr. Millan pay her $850,000 - or she would be going 'to the press.' Mr. Millan refused to respond to this threat, and this interview is the result," a rep for Millan wrote in a statement obtained by PEOPLE on Tuesday.
The statement continued, "As everyone knows, Cesar Millan is one of the world's most prominent dog training experts. Over his extraordinary career, Mr. Millan has fostered, and helped - literally - thousands of behaviorally troubled animals dogs - often with dogs at risk of being 'put down.' "
The rep added that Matiss was "well aware of this" while visiting Millan's training facility and "repeatedly returned to his property and ranch after the incident."
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In her lawsuit, Matiss also claimed that Junior had previously bitten other people and attacked other dogs as well, including one dog owned by Queen Latifah. There, Matiss alleges that Junior "mauled one of [QL's] dogs to death" and said that Millan covered up the incident by telling his staff that they were to tell the actress that her dog was hit and killed by a car.
On Tuesday, Millan's rep called that accusation "a blatant lie."
Attorneys for Matiss did not immediately respond to PEOPLE's request for comment.
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According to legal documents, Matiss said that the dog was "unsupervised and unleashed" when he began to attack her, biting her numerous times on the legs. When she arrived at an emergency room after the incident, TMZ said her "injures were severe." The athlete claims the occurrence also stopped her from later competing in her sport due to pain.
In the lawsuit, Matiss alleges that Millan was aware of his dog's violent tendencies but still allowed him to go without a leash.
In the lawsuit, which is ongoing, Matiss said that the bites she obtained have left her injured and she has suffered both physically and emotionally since the occurrence. TMZ reported that she is suing for unspecified damages.