A man was swimming with friends Monday at Florida's Blue Spring State Park when he suddenly disappeared and turned up dead, leading wildlife officers to kill a 12-foot alligator they found nearby.

James Okkerse, 61, was found floating face down near the shore of the swimming area, according to the Florida Fish and Wildlife Conservation Commission. Carol Anen, who along with her husband was swimming with Okkerse, had reported him missing at about 9:10 a.m. after he hadn't returned for roughly 15 minutes.

"I hate to make you guys come out for nothing, but I'm afraid the man has disappeared," she said, according to the Orlando Sentinel. "I was swimming up behind him and it looked like he was kind of like floating ... and when I swam up to see where he was, he was completely gone. Just gone."  

She recalled her husband had seen an alligator and called for the two to leave the water, but apparently Okkerse didn't hear the warning and continued swimming, ultimately leading to his end.

FWC officials arrived on the scene, and killed a 12-foot alligator that they found nearby, reported FOX's Florida affiliate FOX 35. The reptile was identified to be the same one spotted in the swimming area several times on Sunday, prompting them to close the swimming area. The gator was not spotted again until the time of the attack.

The FWC say are working to determine whether the alligator is to blame for the attack and will reach their conclusion once the autopsy's results come arrive, according to the New York Daily News.

They do note, however, that even if the animal wasn't responsible for the killing, the creature would have been killed anyway since it had become too large, and thus posed a threat to guests at the state park.

Okkerse's family and friends are now left waiting for the results as they cope with their loss.

"It's just a shock," his cousin John Lommerse said. "It's a shock to the whole family ... you don't expect it."