Law enforcement officials searched Friday for a man who reportedly was seen at the freeway rest stop southeast of Boise where a badly abused and malnourished boy was found Wednesday.

Ada County Sheriff Vaughn Killeen said detectives wanted to interview the unidentified man whom a witness reported seeing with the boy in a closed stall inside the restroom at the Blacks Creek Rest Area off Interstate 84.A witness reported seeing the man about 2:30 p.m. Wednesday, Killeen said. The boy was found abandoned in the restroom about 45 minutes later, wimpering and wearing only a T-shirt.

The only thing the witness could tell officials about the man was that he was wearing worn cowboy boots. The sheriff said he may have been driving a small off-white pickup, possibly a Mazda or Ford Courier.

The 8- or 9-year-old boy, who officials have dubbed "Johnny Doe," remained Friday at St. Luke's Regional Medical Center. He was being treated for bruises, scrapes, burns and malnutrition, and was undergoing tests to determine his level of development.

Dr. Thomas Cornwall, the pediatrician who has handled the boy's case, said there was evidence of developmental retardation.

He still had not spoken, and Cornwall said it would be difficult for him to overcome the trauma of what appears to have been a lifetime of abuse.

The boy is sleeping, eating and watching television, the doctor said. Wednesday night, nurses found him drinking out of a toilet bowl, which Cornwall said was another indication of how he had lived.