EUGENE, Ore. -- A 12-foot snake attacked a female employee of a pet store, prompting assistance from police, firefighters and emergency personnel Thursday.

Sergeant Ryan Nelson had never tangled with a snake larger than a garter snake before Thursday.

All that changed, however, when he responded to a 911 call at 3:41 p.m. to find a woman in a Eugene pet store completely wrapped by a 12-foot Burmese python that was slowly constricting around her, police said.

Nelson saw the woman was in grave danger and feared for her life. But as he pulled out his knife in preparation to save the woman, matters got more difficult.

She pleaded with Nelson not to injure the snake.

So at risk to himself, Nelson complied and began his rescue attempt by trying to wrench the snake's mouth off of the woman's finger -- the snake had begun its attack by biting onto the woman's finger, wrapping itself around her wrist, arm then shoulder and moving toward her throat, police said.

Nelson managed to pry the snake's jaws partially off the woman's finger. A few of the snake's teeth got lodged in his thumb. Then emergency personnel used a screwdriver to free the woman's finger from the jaws of the reptile.

Nelson then put his own squeeze on the snake’s neck and was helped by fire and EMS members to unwrap the snake from the woman.

Nelson then started the task of returning the snake to the cage – the entrance to which was above head level.

The snake fought itself free and lunged for Nelson, but he grabbed the head again and finally wrestled it into its enclosure.

As he shut the door the angry serpent's head shot forth once more, trying to get in one last bite.

The jaws met only glass.

Neither the woman nor the snake was seriously injured in the ordeal, police said.