An out-of-control, 200-pound pet chimpanzee that had recently been given Xanax apparently went berserk and mauled a woman in Connecticut, leaving her in critical condition.
The owner of the former TV star chimp Travis stabbed him multiple times after the Monday attack, but to no avail. Police were called to the scene and say they had no choice but to shoot and kill the pet-gone-wild.
The bizarre scene unfolded in Stamford, when Travis suddenly attacked and tore up the face of 55-year-old Charla Nash, who was visiting his owner Sandra Herold Monday night.
Nash was taken to the hospital with severe wounds and remained in critical condition Tuesday.
"He bit both of her hands off and the cop told me he just kept eating her. It's terrible," Lynne Mecca, a friend of the victim, told CBS News.
The animal had recently been given Xanax, an anti-anxiety drug that is used for pets as well as humans, because it had become agitated.
Stamford Police Capt. Richard Conklin said Herold gave Travis the drug in some tea. The medication can initially cause an increase in anxiety in animals until they adjust to it.
Authorities say there was no known provocation for the attack.
The victim suffered "a tremendous loss of blood" from serious facial injuries, according to Conklin.
Nash was in critical condition Tuesday after suffering what Stamford Mayor Dannel Malloy called "life-changing, if not life-threatening," injuries to her face and hands.
Her sister-in-law, Kate Nash, said Tuesday morning that Nash underwent surgery Monday night and came out of it "OK."
Herold and two officers also were hurt, though authorities said the extent of their wounds was not immediately known.
The 15-year-old chimp once starred in TV commercials for Old Navy and Coca-Cola.
Police said they don't know why Travis attacked Nash as she got out of her car to visit Herold. There was speculation that it may have been because she had recently changed her hairstyle and the animal could have thought she was an intruder.
Conklin said Herold wrestled with the chimp, then ran inside to call 911.
"She retrieved a large butcher knife and stabbed her longtime pet numerous times in an effort to save her friend, who was really being brutally attacked," Conklin said.
Travis ran away and started roaming on Herold's property as police arrived. Officers set up security so that medics could reach the critically injured woman lying on the ground, Conklin said.
But the chimpanzee returned and went after several of the officers, who retreated into their cars, Conklin said. Travis knocked the mirror off a cruiser before opening its door and starting to get in, trapping the officer.
That officer shot the chimpanzee several times, Conklin said.
The wounded chimpanzee fled the scene, but Conklin said police were able to follow the trail of his blood: down the driveway, into the open door of the home, through the house and to his living quarters, where he had retreated and died of his wounds.
"He's been raised almost like a child by this family," Conklin said Monday. "He rides in a car every day, he opens doors, he's a very unique animal in that aspect. We have no indication of what provoked this behavior at all."
Conklin said the chimp has been sick with Lyme disease, so the drugs might have made him anxious.
"Maybe from the medications he was out of sorts," he said. "We really don't know."
Police have dealt with him in the past, including an incident in 2003 when he escaped from his owners' vehicle in downtown Stamford for two hours.
Officers used cookies, macadamia treats and ice cream in an attempt to lure him, but subdued him only after he became too tired to resist.
At the time of the 2003 incident, police said the Herolds told them the chimpanzee was toilet trained, dressed himself, took his own bath, ate at the table and drank wine from a stemmed glass.
He also brushed his teeth using a Water Pik, logged onto the computer to look at pictures, and watched television using the remote control.
Colleen McCann, a primatologist at the Bronx Zoo, said Tuesday that chimpanzees are unpredictable and dangerous even after living among humans for years.
"It's deceiving to think that if any animal is ... well-behaved around humans, that means there is no risk involved to humans for potential outbursts of behavior," she said. "They are unpredictable, and in instances like this you cannot control that behavior or prevent it from happening if it is in a private home."
The Associated Press contributed to this report.