A 13ft (4m) alligator has been killed, police say, after it was spotted in Florida with the remains of a woman in its jaws.

A witness told local media he saw the alligator in a Largo canal clutching a lower torso in its mouth.

Pinellas County Sheriff's Office said the animal was killed and confirmed the remains of 41-year-old Sabrina Peckham were found in the waterway.

An investigation will determine the circumstances behind the woman's death.

Police said deputies were called at 13:50 local time on Friday after a report of a body in the waterway.

Jamarcus Bullard said he was walking to a job interview when he spotted the alligator with what initially looked like a mannequin in its mouth.

"I noticed it had a body in its mouth - like a lower torso - so once I saw that I ran straight to the fire department," he told local broadcaster Fox 13.

"It was my first time seeing a gator in real life so I was like it's pretty cool, but once I saw what it had I was like 'is that like a mannequin?'

"It was pale and white."

"It was just clamped onto it, and swam backwards to the bottom of the canal... I just couldn't believe it was real," he said in another interview with 10 Tampa Bay.

A fundraising page has been set up for Ms Peckham by her family, who said the woman was living in a homeless camp near the wooded area at the time of her death.

Breauna Dorris, who said she was the victim's daughter, wrote on Facebook: "It is believed that she may have been walking to or from her campsite near the creek in the dark and the alligator attacked from the water.

"No one deserves to die like this."

Authorities said the alligator was humanely killed and removed from the waterway before a police dive team recovered the remains of Ms Peckham.

News footage shows a huge alligator sprawled beside a road surrounded by police and emergency vehicles.

The Medical Examiner's Office is yet to determine the cause of death.

Nearby residents said they had seen small alligators in the area before, but not of the size of the animal found in this case.

Jennifer Dean told 10 Tampa Bay: "It's crazy. My kids walk by there all the time. So it's really scary. I've seen four or five-feet gators but nothing that big."

Mr Bullard added: "I'm going to get me a bike or start catching the bus to work. They have small little gates, but somebody died."