A 13-year-old boy whose mother reported him missing four years ago was found by police hidden behind a false wall in his father's Georgia home, US media said.

Authorities arrested five people including the father and stepmother, in Jonesboro, near Atlanta, the local WXIA news network said, showing moving footage of the boy cuddling up to his mother, both in tears, as they were reunited on Saturday.

Clayton county police were called to a house late on Friday, but Police Sergeant KT Hughes said its occupants denied any knowledge of the child to officers.

Just to be sure, police searched the house. They found nothing, the report said.

But when police hours later received another call seeking help at the house, they returned. As a second search was being done, the boy was able to call his mother and tell her where he was being held, reports said.

She directed police to a false wall, hidden by towels, enabling them to find him.

The apparent hiding space was above the garage of the home, WXIA said.

"It shocked all of us, honestly," said one neighbor. "They were really nice people, they were open. They were like, 'Hey, come over any time you want.'"

Police told Atlanta's Channel 2 the mother had apparently reported the child missing to child welfare authorities in 2010, but not to police, possibly because she was an immigrant and unfamiliar with the legal system.

However, authorities said there were still many unanswered questions over custody and why police had not been involved earlier. They said the child would remain with family services for the time being.

The father and stepmother, Gregory Jean, 37, and Samantha Joy Davis, 42, and three others were charged with obstruction, false imprisonment and cruelty to children.

Neighbors said the boy was seen at times working in the yard, and that they heard he was home-schooled, reports said.

(China Daily 12/01/2014 page11)