The child was discovered in a ditch near Magnolia School off Highway 301 after dozens of people, including law enforcement officers, searched the area near the school.
Investigators say 3-year-old Jay Florez wandered outside andwas reported missing around 11 a.m.
Family members say Flores couldn't wait to see what his mom bought him at the store.
"His mother had promised to bring him a toy back," his aunt Ann Hardin said. "So he just ventured out to go meet his mama looking for the toy."
Sheriff's deputies say the child's grandmother was watching him, but was in another part of the home when he wandered off.
Around 2 p.m., the child was found in a water-filled ditch off Rozier Church Road about 200 yards from the mobile home.
Jennifer Wynn, a member of the Saddletree Volunteer Fire Department, was one of dozens of volunteers who searched the area for 90 minutes before making the grim discovery.
"The shoes were floating on top and we stuck a pole in the water and pulled the child out of the water, CPR was administered," she said.
Rescue crews rushed the boy to Southeast General Hospital where doctors worked for more than four hours to save his life.
Authorities say just after 6 p.m. Flores died.
The Robeson County sheriff's department says investigators are still working the case and no charges have been filed. The Department of Social Services is also investigating.