Authorities found human remains inside a 13-foot crocodile while searching for a missing fisherman

• Andrew Heard went missing on Thursday while fishing in Australia.
• Authorities found human remains inside of a 13-foot crocodile during the search for Heard.
• Officials have killed two crocodiles amid the investigation.

Authorities found human remains inside of 13.8-foot crocodile while searching for a missing fisherman in Queensland, Australia, on Sunday, according to a press release from the Queensland Police.

Investigators have captured and killed two crocodiles amid the search for the fisherman, 69-year-old Andrew Heard, CNN reported.

Heard was last seen around 3 p.m. on Thursday, according to officials. He intended to fish on Hinchinbrook Island and was supposed to come home about an hour after he left, but he never returned.

Police, coast guard officials, and officers for the Queensland Department of Environment and Science have been searching for Heard ever since.

On Saturday, investigators discovered human remains believed to be Heard's in the search area, according to the Sunday statement from the Queensland Police.

Later that day, officials from the Department of Environment and Science caught and euthanized the 13.8-foot crocodile. They found human remains inside of the creature after a necropsy, Queensland Police said.

Authorities believe the remains are Heard's, according to the press release.

Officials also captured and killed a second crocodile on Sunday, CNN reported. The necropsy on the 9.8-foot crocodile had not been completed at the time this article was written, but the animal appeared to have been involved in the incident.

"At this stage we can only confirm that we've found human remains in the first," Andrew Cowie, the acting inspector of Queensland Police, said at a press conference on Monday, as reported by CNN. "I believe that we've got the two crocodiles involved."

Cowie went on to say that both crocodiles were captured near the area Heard was thought to be fishing, and officials also found a damaged boat in the search area, which is also being investigated, according to CNN. "This is a tragic incident," Cowie reportedly said at the conference.

Heard's disappearance marks the third crocodile attack in Queensland in the last month, as The Guardian reported.