The body of a 4-year-old autistic boy who went missing while visiting his grandparents in South Carolina was found in a pond Friday, authorities said. Jayden Morrison, who is non-communicative, was last seen Wednesday at his grandmother's house in Little River near Myrtle Beach. He was found in the pond, not far from the home, at 10:45 a.m., Horry County Lieutenant Raul Denis said during a news conference Friday. Horry County Coroner Robert Edge said an autopsy showed Jayden drowned. Edge said Jayden likely died shortly after he was reported missing on Christmas Eve. Investigators believe he wandered into the water.

Hundreds of volunteers, police and rescue crews began a third day of searching Friday for the young boy in remote areas and bodies of water, according to the Horry County Police Department. His body wasn’t discovered until they started draining the pond.

Jayden's mother, who is from Westchester County, New York, left him in the care of his grandmother on Christmas Eve during the family's visit. The grandmother told police that she turned around when the boy disappeared, according to NBC's Myrtle Beach affiliate WMBF.

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In the water below tree on right side is where police found Jayden Morrison @wmbfnews pic.twitter.com/h8ZEilXc3X — BrennanSomersWMBF (@brennansomers) December 26, 2014

Pond where police found the body is behind a home off Vermillion Dr, Jayden's family is at a home off Sultana Dr, the pond sits in between — BrennanSomersWMBF (@brennansomers) December 26, 2014

— Elisha Fieldstadt