Florida wildlife officials searched Thursday for an alligator that attacked a 90-year old woman and nearly severed her leg, which doctors later had to amputate.

Longtime resident Margaret Webb was walking near her home in a small southwest Florida community Wednesday when an eight-foot long alligator lunged out of a canal and bit Webb's leg.

Florida Fish and Wildlife Conservation Commission spokeswoman Gabriela Ferraro said a neighbor was driving by and saw the alligator trying to drag Webb into the water. The man - Dwyane Daniels, who Ferraro called "a good Samaritan" - pulled out a gun and tried to shoot the gator.

The reptile crawled away and Daniels dialed 911. Webb was airlifted to a Naples hospital, where she is in critical condition.

Ferraro said officers initially thought the alligator had swallowed Webb's leg, but that wasn't the case. Her leg was "barely attached" after the attack and was later amputated, Ferraro said.

Officers want to find and trap the alligator, she said.

"When a person is bitten, our priority is to remove the suspect alligator," she said.

Because Daniels shot at the alligator, it's possible that it is already dead. Daniels is an airboat operator in the Everglades and has known Webb his entire life. Residents describe Webb as being "like a grandma" to everyone in the small community.

About five people are bitten each year in Florida by unprovoked alligators, officials said.

The attack happened in Copeland, a small town in Collier County with a population of 275 people that is located in southwest Florida near the Everglades.