In seven years working crimes against children, the Idaho detective had never seen anything like the emaciated, battered boy found whimpering in a freeway rest stop.

"Overall, it was the worst case of abuse and circumstances surrounding abuse that I have ever seen," said the detective, Rita Rowe. "He was, and I want to choose the word carefully, pitiful."Rowe was on duty at the Ada County sheriff's office in Boise on Jan. 4 when the child, pocked with cigarette burns and clad only in a T-shirt, was brought in by a deputy.

For three days, Rowe and others tried to put a history to the mute boy they called Johnny Doe. Then a Utah mother called Idaho authorities when her 5-year-old son recognized the abandoned child on a television newscast as Eddy Tuinman, age 7.

Hours later, Eddy's parents were arrested in central Utah on an Idaho warrant for felony child abandonment. Suburban Salt Lake police had been looking for the couple on a charge that they had illegally tapped into a natural gas line at their rented home.

Deborah Tuinman, 28, told investigators she awoke from a nap in the family car to find Eddy gone. Her husband, Edward Donald Tuinman, a 29-year-old itinerant mechanic, claimed to have left the boy with social services workers in Boise, she said.

By week's end the couple had waived extradition and will be returned to Idaho by Jan. 23. After four days in a hospital, Eddy was placed in foster care, and three other Tuinman children were in protective custody in Utah.

When Eddy was brought in, Rowe gave him a teddy bear as he cowered in blankets on the floor, flinching at sudden movements and so weakened by hunger he could neither sit nor stand unaided.

"He touched it and rubbed it and felt the fur," she said. "He had kind of a surprised look on his face. His reaction was that of a child who'd never played with a toy before."

But when Rowe tried to help the boy to a bathroom, he panicked and clung to her, making inarticulate sounds of disapproval. Later investigation showed the child may have been locked alone in bathrooms for hours with only toilet water to drink.

Equally appalled was Laurie Gillis, a victim-witness coordinator for the county prosecutor and, for several hours, Eddy's anchor.

Gillis sang to the boy as she held him "and he would just close his eyes and almost go to sleep," said Rowe. "That was the only thing he asked for was love. Not food, not anything except the good touches."

At St. Luke's Regional Medical Center, Eddy refused to let go of Gillis and the doctor had to examine him in her lap. He found the child weighed 44 pounds, showed evidence of healed-over fractures and was mentally retarded, although further tests were needed to judge its severity.

When he was released to foster parents on Jan. 8, Eddy could laugh and seemed to comprehend much of what was said to him, said hospital spokeswoman Rita Ryan. His temporary parents have experience with other handicapped children.

But as more is learned about Eddy, only piecemeal information is available on his parents. It is known they lived in the Salt Lake area for several years and in Washington state the last three months of 1988.

Investigators believe Eddy was abandoned as the family traveled through Idaho on its way to Arizona, where Tuinman, who has a history of petty offenses, was going for work.

The family included an 11-year-old girl and two other boys aged 6 and 11 months. They had lived in a ramshackle cabin in Buena, Wash., about 10 miles south of Yakima.

Cabin owner Ralph Conners said the Tuinmans left Jan. 3, the day before a motorist found Eddy at the I-84 rest stop southeast of Boise.

He said the Tuinmans got by on a monthly welfare check of about $800, borrowing food and wood from neighbors when the money ran out. He said he witnessed no abuse of the children.

In Salt Lake City, the mother of the boy who identified Eddy, Debbie Maddera, said she used to chat with Mrs. Tuinman, but the woman's husband kept to himself.

"She seemed like she was really protective over (Eddy)," Maddera said. "I never really seen her hit him or yell at him . . . I never seen any beatings or any sign of that."

But Detective Patti Smalley in Sandy, where the Tuinmans faced the theft charges that were dismissed to speed their extradition, is convinced Eddy suffered long-term physical abuse.

Smalley drove the other Tuinman children back to Salt Lake City after their parents' arrest. A doctor found no sign they had been abused, but they were uncommunicative.

"It was real hard to get much because they're really protective of their parents," Smalley said. "The kids were worried about their mother. They were scared and wanted to be with her."

She speculates Eddy took the brunt of punishment in the family because the other children were not surprised at his condition.

"To them, abuse isn't abuse," Smalley said. "To them, it's just been normal."