Florida wildlife officers captured an alligator Saturday they believe was responsible for fatally attacking a woman while she was out jogging.

The three-metre-long alligator was trapped under the bridge where Yovy Suarez Jimenez, 28, was last seen, said Dani Moschella, a spokeswoman for the Florida Fish and Wildlife Conservation Commission.

Two human arms were found inside the alligator's belly, Moschella said.

An autopsy showed she died of bleeding and shock from alligator bites, Reuters said.

"The alligator attacked her and basically amputated her arms, bit her on the leg and back and pulled her into the water," said Dr. Joshua Perper, the Broward County medical examiner, who performed the autopsy.

"She died extremely fast. By the time she was pulled into the water, she was already dead."

Authorities told the Associated Press they aren't sure how the alligator attacked Suarez.

Witnesses reported seeing a woman matching Suarez's description dangling her feet over the water's edge Tuesday, while a medical examiner said the alligator attacked while she was on land and then dragged her body into a canal in Sunrise, a northwest suburb of Fort Lauderdale.

Suarez's death is the 18th confirmed fatal alligator attack in Florida since 1948, Moschella said. Nine other deaths are unconfirmed.