US:Investigators trying to determine how a tiger escaped from its San Francisco Zoo enclosure on Christmas Day - killing one man and mauling two others - combed the zoo grounds last night to look for clues.
Authorities do not believe more people were attacked, but they want to inspect the area in daylight.
Zoo officials are still uncertain how long the tiger, which last year badly mauled a zookeeper, was loose before being shot dead.
The three men who were attacked on Tuesday while visiting the zoo were in their 20s, police spokesman Steve Mannina said. The attack occurred just after the 5pm closing time, on the east end of the 125-acre grounds.
They suffered "pretty aggressive bite marks", Mr Mannina said.
The injured men were listed in critical but stable condition at San Francisco General Hospital. Physician John Brown told the San Francisco Chronicle they had suffered deep bites and claw cuts to their heads and upper bodies.
The Siberian tiger, Tatiana, was the same giant cat that attacked a zookeeper a year ago during a public feeding, said Robert Jenkins, the zoo's director of animal care and conservation.
The 300lb female did not leave through an open door, Mr Jenkins said. But he could not explain how it escaped - the tiger's enclosure is surrounded by a 15ft moat and 20ft high walls.
"There was no way out through the door," Mr Jenkins said. "The animal appears to have climbed or otherwise leapt out of the enclosure." The first attack happened outside the Siberian's enclosure - the victim died at the scene. Four officers, responding to an emergency call, came across his body when they made their way into the dark grounds, Mr Mannina said. It was not immediately clear who placed the call.
Then they saw the second victim. The man was sitting on the ground, blood running from his head. Tatiana sat next to him. Suddenly, the cat attacked the man again, Mr Mannina said.
The officers approached the tiger. Tatiana started moving in their direction. Several of the officers fired, killing the animal. Only then did they see the third victim, who had also been mauled.