Ada County Sheriff's deputies searched Thursday for the parents of a battered boy, believed to be about 9 years old, found abandoned and half-naked Wednesday night at a freeway rest stop east of Boise.

Sheriff's Captain Roy Holloway said the boy, wearing only a T-shirt, was found by passers-by at 5 p.m. in the restroom at the Blacks Creek Rest Area on Interstate 84.The boy appeared malnourished, shivering and had burns and blisters on his arms and legs, Holloway said. The boy did not speak to authorities who tried to interview him and was rushed to St. Luke's Regional Medical Center in Boise, where he was being evaluated late Wednesday.

"We didn't see any large or life-threatening injuries on him, but there were burns and some scrapes and abrasions on him," Holloway said. "It looked like he had really been mishandled. I can't imagine a kid getting those kinds of scrapes and bruises unless he was battered around quite a bit."

Officers said they did not know whether the boy was mute or was too frightened or traumatized to speak.