EL PASO, Texas (AP) _ Exactly what an unidentified deaf-mute boy has gone through remains a mystery, in spite of his repeated drawings showing a crashed plane with bodies that may be his parents, an FBI agent said Saturday.

''We have no clues at all,'' said agent Terry Kincaid.

Of the boy's drawings, he said, ''We have no idea how much of his sketches are his own idea or his imagination or maybe re-creations of popular television shows.''

The boy has been in a child protective service center since November in Juarez, Mexico, where he was found on the streets, but investigators suspect he might be from the United States because of his preferences in food and games.

The boy is believed to be 7 or 8 years old and is called Sabat by welfare workers because he was found on a Saturday.

Investigators have discovered that the boy has been in the United States at least once, Kincaid said Saturday.

Before taking him to the center, Guadalupe de la Vega, the Juarez woman who found him wandering about, took him to see an ear specialist in New York and then brought him back to Mexico, Kincaid said.

The woman's first encounter with the boy was surprising.

''He was on the streets in Juarez and this woman thought he was begging. She gave him a thousand pesos and he handed it back to her,'' Kincaid said.

''From the way he keeps drawing the same pictures, and has his clothes packed, I think he is desperate to find his way back home,'' said Leticia Cota, a social worker in Juarez.

''We are continuing efforts to develop leads as to this little guy's identity through whatever means possible. It's going to be an uphill struggle,'' said Kincaid.

Kincaid said that during the trip to New York, the boy became excited when he saw a soldier. ''We're exploring the possibility that his father may have been a policeman or soldier, or someone associated with a uniform,'' he said.

Kincaid said Mexican social workers initially thought the boy was Mexican, until he showed a preference for hamburgers over Mexican food.

He draws a house with a pitched roof, not common in Mexico, and indicates it was his home. He excels at video games with which few Mexican children are familiar, and is familiar with U.S. currency.

Mexican social workers contacted their El Paso counterparts last month, and the Center for Missing and Exploited Children in Washington sought the help of the FBI in El Paso last week to find the boy's identity.

At least two leads are being pursued, said Luis Torre, a caseworker for the Texas Department of Human Services in El Paso.

''Law officials think he resembles a boy from Illinois who was reported missing about three years ago, or a boy from a military family who lived in Alaska,'' Torre said.

Kincaid said officials expected to receive by Monday copies of footprints of a child who was kidnapped from Decatur, Ill., in October 1985. The description of the kidnapped child was forwarded from the Center for Missing and Exploited Children.

Kincaid said the boy is in good health. ''He seems to have a good attitude notwithstanding everything he has apparently gone through,'' Kincaid said.

His pictures of a crashed airplane include people that he describes as his father, mother, younger sister and himself and have the numbers ''28D, 23'' written under the airplane.

During an interview Friday, the boy pointed to scars on his left knee, stomach and back, and back to the crash drawing. He pointed to a drawing of himself walking away from the crash while the figures believed to be his parents and sister lay dead.

The age of the boy's scars led doctors to believe that if they had been caused by a crash, it would have been two to three years ago.

Social workers said that through drawings and other communication, the boy has revealed background details that indicate his father was missing four fingers on his right hand and had a mustache and that the family lived in a place that had knee-deep snow, heavy rainfall, mountains and trees.

The boy is 4 feet 6, has dark blond to light brown hair and a slightly freckled white complexion.