WTVC reports the boy's mother, Monica Hall, and her husband, Dennis Couch, were arrested at their home on Monday.
Rhea County Sheriff's Department Det. Rocky Potter said when he went over to the house, a child was yelling "ow, ow."
Det. Potter said he found a U-bolt on the floor of an empty bedroom without carpet and only a small mattress inside. Attached to the bolt was a dog harness and a three-foot-leash made with belts and electrical tape.
According to Potter, the child was sometimes put into the harness for hours at a time as a punishment. He says Hall gave them an explanation but cannot elaborate due to the ongoing investigation.
Potter said the child cannot speak at age level, so investigators have been unable to talk to him about his treatment.
"He did have some physical injuries that were photographed, but like I said, I think the mental part would be the most extreme," Det. Potter said.
The couple will appear in court on August 4.
Two other children were in the home at the time. They are now staying with relatives.
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