Seven Texas children were discovered abandoned at a Nigerian orphanage, suffering from disease and malnutrition, and have been brought back to the United States.

Child Protective Services of Harris County, which received emergency custody of the children Monday, is investigating accusations that the children's adoptive mother abandoned them in Nigeria in October and later went to work in Iraq as a private contractor. The Houston woman, whose identity was not released, allegedly left them at a Nigerian school that later discharged them for nonpayment of tuition.

The children returned to Texas on Friday.

Three of the children were hospitalized with malaria and later released, said CPS spokeswoman Estella Olguin. They all were thin and covered with mosquito bites and scars, officials said.

The three boys and four girls, ages 8 to 16, were discovered in late July by a visiting Texas missionary, who notified House Majority Leader Tom DeLay and Sen. John Cornyn, both Texas Republicans, said Stuart Roy, a spokesman for DeLay.

The lawmakers contacted CPS, the State Department and the ambassador in Nigeria, and the children were given papers allowing reentry into the United States.

Now they are living in two Houston foster homes.

"It's horrible, horrible," Olguin said. "I haven't seen anything like it. Seven children fending for themselves in a foreign country where they have no family members."

Four of the siblings were adopted from Houston in 1996, followed by a set of three siblings from Dallas in 2001, according to authorities who interviewed the seven children and their adoptive mother.

The woman took all the children in October to Nigeria, where a relative of her fiance lived. The children were enrolled in school, and the mother returned to Houston about 30 days later. She went to work in Iraq in April.

But the children were removed from school because payment for their tuition stopped. Nigerian child-protection authorities found the children in a wooden shack, malnourished and sick, and moved them to an orphanage in late July.

A minister from a San Antonio church alerted lawmakers after he overheard the children speaking with American accents.

Olguin said their adoptive mother was at the hearing Monday at which a state district judge ordered the children to be returned to CPS custody. State officials will determine whether criminal charges will be filed against the adoptive mother.