US authorities have captured and killed an alligator that they believe fatally attacked a woman while she was walking her dogs near a Florida lake.

Florida Fish and Wildlife Conservation Commission officials said that a post-mortem confirmed the alligator bit the woman and they believe she is dead.

They did not provide any other details or identify the victim, but said multiple units are searching for her body.

A witness told authorities he saw the woman walking two dogs and then noticed the dogs alone, barking near the water. One of the dogs had a fresh injury, a gash on its side, said Davie Police Detective Viviana Gallinal.

The witness called police when he could not find the woman.

Alligator Attack
Police divers arrive at Silver Lakes Rotary Nature Park (Wilfredo Lee/AP)

Trappers have spotted a 12ft alligator in the pond in Silver Lakes Rotary Nature Park, Ms Gallinal said.

Jim Borrelli, a friend of the woman, said she and her husband have walked their dogs in the park previously. The couple did not live in the neighbourhood but he said she liked to find different places to walk the dogs. Residents said they often saw her walking them in the area.

Mr Borrelli said the woman’s husband, who is out of town and trying to fly home, sent him to the park to get more information after being contacted by Davie Police. Mr Borrelli said he was also asked to break the news to the couple’s son, who is in his 20s and lives in New York.

“I’m praying that nothing happened to her,” Mr Borrelli said.

A man who identified himself as the woman’s brother and several other family friends gathered at the scene. He declined to talk but friends described the missing woman as a great friend who loved to cook.

Alligators are opportunistic feeders that will eat what is readily available and easily overpowered. Feeding wild alligators is illegal because they could lose their fear of humans.

Fatal attacks on humans remain rare, however. According to the wildlife commission, the likelihood of a Florida resident being seriously injured during an unprovoked alligator incident in Florida is roughly only 1 in 3.2 million.

From 1948 to 2017, the commission has documented 401 people bitten by alligators, including 24 fatalities. The most recent death occurred in 2016, when a two-year-old boy playing near the water’s edge at a Walt Disney World resort was killed.

Alligator Attack
Police block the entrance to Silver Lakes Rotary Nature Park (Wilfredo Lee/AP)

The park where the woman disappeared on Friday is near the Seminole Hard Rock Hotel & Casino, a major Miami-area tourist and entertainment attraction.

Authorities closed the park on Friday but passers-by said they were not surprised to hear about an alligator lurking in the water.

“Any body of water in Florida, you’ve got to know at some point or another there’s an alligator,” said Heather Porrata, who lives nearby.

Sharon Estupinan said a park ranger warned her to walk her dogs farther away from the water’s edge after she saw a 10ft gator in the pond three days ago.

“I was afraid,” she said. “Every time I walked the dogs during the day, I was like, ‘Oh, my God, I’ve gotta keep away from there. I have to call my dogs,’ so they wouldn’t get close to the water or any of the trees near there because he could be hiding. Although, he’s really big. I don’t think he could really hide.”