A nappy-wearing chimpanzee has been shot and killed by police after viciously attacking his owner's friend.
Witnesses said the 80kg primate dubbed "Travis" pounced on the woman and mauled her, forcing owner Sandra Herold to use a butcher's knife to pry him off, the New York Daily News reports.
When police arrived and attempted to clear a path for an ambulance, Travis ripped the side mirror off their cruiser and tried to open a door.
The officer inside fired several shots, killing the ape.
The attack is believed to have happened at Ms Herold's home in Stamford, Connecticut, yesterday.
Ms Herold and two police officers were also injured in the attack.
The unidentified victim remains in a critical condition with severe injuries to her face and hands.
The incident may come as a shock to Ms Herold who ensured that the 16-year-old was well-trained and accustomed to human interaction.
Travis was able to draw his own bath, brush his teeth and log onto a computer to look at photos.
He enjoyed drinking wine, watering plants and watching baseball on television.
In his younger days Travis appeared in a Coca Cola advertisement.
Stamford police Lieutenant Richard Conklin said the attack was out of character for the chimp.
"He's been raised almost like a child by this family," Conklin said.
"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 behaviour at all."
Conklin said the chimp had been ill from Lyme disease, "so maybe from the medications he was out of sorts. We really don't know".
The chimp is well-known amongst locals because of an incident in 2003 when he leapt from a moving vehicle driven by his owners after he was startled by something thrown through the car window.
Travis played at a road intersection for several hours before police were able to recapture him.
Officers used biscuits, macadamia treats and ice cream in an attempt to lure him, but subdued him only after he became too tired to resist.