An elephant broke loose from its chains at Lion Country Safari, killed the park's game warden and charged toward the San Diego Freeway before being subdued by tranquilizer darts fired from a police helicopter and captured.

Game warden Lee Keaton, 34, of Lake Elsinore, died of head injuries after trying unsuccessfully to secure the animal, authorities said.

After charging county fire department medics, the elephant trotted into a field adjacent to the busy 405 Freeway, Irvine Police Sgt. Pat Rogers said. Scores of shoppers from a nearby swap meet were evacuated when the elephant escaped and freeway traffic was halted for three hours. There were no reported injuries.

The animal was returned to its compound after its rampage, the third incident in a year at the popular park.

Last October, a 2-year-old boy was mauled by a Siberian tiger that escaped its cage. The boy survived and his parents filed a $2 million million damage suit. In March, a park employe was knocked to the ground and scratched by a chimpanzee.

In 1978, Bubbles, a hippopotamus, slipped under a fence at the park and wouldn't budge from her lake hideout for weeks. She eventually died after being shot with a tranquilizer gun.