Killer Tiger's Escape a Mystery

The San Francisco Zoo remained shuttered today as investigators and grieving family alike struggled to understand how a Siberian tiger was able to escape her cage and maul 17-year-old Carlos Souza to death. "This is very rough on us," said an uncle. "He was a great kid." Police have opened a criminal investigation to determine if human involvement played a role in the cat's escape.

Amid speculation that the cat was taunted, one zookeeper said that escaping its 18-foot wall and 20-foot moat was virtually impossible. "It just doesn't feel right to me," he said. "It just doesn't add up to me." “Something happened to get that cat agitated, to do what it did,” said the zoo director, who called Tatiana "mellow." The friends were in stable condition yesterday. The tiger was killed at the scene. (More San Francisco Zoo stories.)