Saturday morning with what appears to be a terrifying alligator attack in Florida. Police captured the massive gator after getting a call about a woman vanishing while walking her dogs. ABC's erielle reshef joins us with more. Erielle. Reporter: Good morning, whit and Paula. Experts say it could have been a case of mistaken identity. A hungry or protective gator mistaking that woman for prey snatching her from the shore leaving tragedy in its wake. A grim discovery in this south Florida lake, a woman vanishing while out for a walk, now presumed dead in an apparent alligator attack. I just want pistols out since we have confirmation that the alligator is in here. Reporter: This 12-foot gator pulled from the murky waters, authorities finding a human arm inside the reptile. Around 9:45 A.M. Friday a witness spotting 47-year-old shizuka Matsuki strolling with her dogs. Moments later the witness noticing the woman had disappeared. I tell people, whether you know there's a gator or not, there's a gator in here. I saw the gator yesterday. Reporter: Police arriving on the scene to find the two dogs roaming alone, one of them badly injured with fresh wounds. No trace of their owner. There's a gator about 300 feet away from us in the middle of the lake. He's just been kind of floating around in this area. Reporter: The animal cornered during the desperate search for the victim. Police now fearing the worst. Initial necropsy revealed human remains in the gator. At this time we believe the victim has been deceased and we will continue the search throughout the night and into the morning. Reporter: While the CDC reports only 11 gator-related deaths in nearly two decades, Florida wildlife experts warn summer is nesting season for the reptiles. In the nesting season you need to be aware of alligator nests and they basically appear to be small mounds of dying vegetation. Anybody walks by a nest, an alligator will come and attack them. Reporter: Gators infesting fresh bodies of water more likely to be aggressive. Authorities are continuing their recovery effort this morning. Florida wildlife experts say it's important to remember never to walk with small children or pets on the banks of fresh bodies of water in Florida especially at dusk and at dawn, that is, guys, when gators are on the prowl, on the hunt and kids and pets can be mistaken as prey. Dusk and dawn. Dusk and dawn. Sometimes people don't know that. It's really terrifying. I didn't know that. Great advice. Thank you very much, erielle. Such a tragedy too. Wildfires out west,