A San Francisco police officer shot and killed a homeless man's dog in Golden Gate Park on Monday afternoon, a police spokesman said. Police said the officer was being bit at the time.

Here's what happened, according to police: at about 4:55 p.m., the officer was trying to wake up the man near Alvord Lake on the eastern side of the park near Stanyan Street when the transient's dog started barking.

The officer backed away, but the dog, believed to be a pit bull mix, broke free, ran toward the officer and bit him.

The officer shot and killed the animal.

The officer was treated back at the police station for the dog bite.