An Easton family is mourning the loss of 6-year-old Onnex Thompson-Hall.

“This is every parent’s worst nightmare,” said Victoria Folino, the child's teacher at Crossroads Center for Children.

Believed to have wandered off, the boy was reported missing at around 10:40 a.m. Sunday near the Washington County Fairgrounds in Greenwich.

“He was the happiest little boy. He talked about his parents. He talked about his siblings. He loved everyone,” Folino said. “He had the biggest imagination on the planet.”

Thompson-Hall was autistic. It was believed he would be responsive to search teams on Sunday.

“I don’t think Onnex has ever met a stranger in his life,” Folino said. “He was extremely sociable.”

State Police, Forest Rangers and other local agencies assisted in the search. It ended shortly before 7 p.m. Sunday, when the little boy’s body was found in a pond near his family’s home in Easton.

“The world is such a darker place without him,” Folino said.

Students and staff at the school were also reeling from the sudden loss on Monday. Police are investigating the incident, but it's believed Thompson-Hall accidentally drowned.

“People are very quick to judge. This can happen to anyone,” Folino said. “You can do the same thing 365 days and on the 366th day, do something different and a tragedy like this can happen.”

The school is collecting donations to help support the family.

“They do have other children,” Folino said. “Onnex is going to leave a big space in their home. He was loved.”