A chimp named Travis who once appeared in TV adverts has attacked a woman and a police officer, according to Stamford's The Advocate.
The ape, which weighed 90kg, mauled a female who was visiting his owner Sandra Herold in Connecticut.
Travis's attack left the woman, who has not been named, suffering from a "tremendous loss of blood" and in a "very serious" condition. Herold stabbed the chimp with a knife to halt his attack on her friend.
Police officers who arrived at the scene were cornered in their car by the animal, who was still acting aggressively. He then climbed in their vehicle, prompting the police to shoot him.
Travis, who appeared in TV campaigns for Old Navy and Coke, was later found dead in Herold's house as a result of the shot wounds.
Stamford's police captain Richard Conklin commented: "[Travis] has been raised almost like a child by this family.
"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."