“The keeper at the Riverside Discovery Center in Scottsbluff, Neb., on Friday afternoon was petting a 40-year-old chimpanzee who apparently did not want to be touched, according to police. When the chimp grabbed the keeper's hand, the keeper started screaming, causing the chimp to scream, police said. This attracted another chimp, who also grabbed the keeper's hand."
Detailed Accounts of Chimpanzee Attacks:
Deadly Animals (UK)
The Book of Deadly Animals (US)