LAFITTE - Search crews are entering their fifth day on the water in a national park in Louisiana in hopes of finding the body of a 4-year-old boy who went missing.

Ellis Boudean disappeared in the water at Jean Lafitte National Historical Park and Preserve Thursday evening, WVUE-TV reported.

Ellis, who has autism, was last seen with a parent as they visited the area that’s mostly dense swampland, the Jefferson Parish Sheriff’s Office said.

Authorities are fairly confident that his body is in the water, a sheriff’s spokesperson said.

“At this point in time, it’s a recovery mission,” Jefferson Parish Sheriff Joe Lopinto told reporters over the weekend. “The child never resurfaced.”

UPDATE: B&S— a local contractor is helping JPSO build a dam out of clay in order to pump all of the water out of the area— the latest effort in the search for 4 y.o. Ellis Boudean, who has been missing since Thursday when he disappeared under the water. @FOX8NOLA pic.twitter.com/uPMB8pKDuQ

— Kaitlin Rust (@KaitlinRustWVUE) July 19, 2021

The area is covered in dense vegetation and teeming with potentially dangerous wildlife, including snakes and alligators, sheriff’s officials said.

Multiple boats, sonar equipment and divers are being used in the search, Lopinto told WDSU-TV.