A 200-pound domesticated chimpanzee that badly mauled a woman in Connecticut had been given the the anti-anxiety drug Xanax because it had been agitated.

The chimp, which once starred in TV commercials for Old Navy and Coca-Cola, was shot dead by police after the violent rampage.

Sandra Herold, who owned the 15-year-old chimp named Travis, wrestled with the animal and stabbed it after it inexplicably attacked her friend Charla Nash.

Nash had gone to Herold's home Monday to help her coax the chimp back into the house. Nash is hospitalized in critical condition.

Authorities say there was no known provocation.

Stamford, Connecticut police Capt. Richard Conklin says Herold gave Travis the Xanax in some tea. Conklin also suggested the animal may have attacked Nash because she was wearing her hair differently and wasn't recognized.

An officer shot and killed the chimpanzee when it tried to get into his police cruiser after Monday's attack in Stamford, Connecticut.

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