The big cat exhibit at San Francisco Zoo was cordoned off as a crime scene today as investigators probed whether a 21-stone Siberian tiger that killed a visitor escaped from its high-walled pen on its own, or was let out deliberately.

A tiger escaped from its pen at the San Francisco Zoo today, killing one man and critically injuring two others before police shot it dead, authorities said.

Shakin' Stevens has been banned from driving for two years after he admitted a charge of drink-driving.