A baby chimpanzee was killed by an adult male chimpanzee inside their exhibit at the Los Angeles Zoo on Tuesday as visitors watched.

Zoo spokesman Jason Jacobs said visitors reported seeing the adult attack the 3-month-old infant but workers could not stop the attack because it is not safe for them to occupy the same space as the chimpanzees.

The baby's mother, a chimp named Gracie who gave birth March 6, "had proved to be a caring mother," the zoo said in a statement.

"Gracie is being allowed to keep the infant overnight to allow her the opportunity to grieve," Jacobs said.

The infant was being gradually introduced to the troop and there had been no indication of aggressive behavior toward her, but chimpanzees can sometimes show surprising aggression.

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