The operator of a California wildlife sanctuary near Bakersfield (search) won't face criminal charges in connection with an attack by two chimpanzees (search).

The animals critically injured a man last month.

Authorities say the operator — Virginia Brauer (search) — was not to blame because the animals apparently escaped on their own.

Kern County officials say one of the chimps apparently figured out how to reach through a tight space between a chain link fence and a wall, pull out a steel pin and slide a door open.

The animals chewed off part of a man's face and mauled other parts of his body before Brauer's son-in-law shot the animals to death.