It had been 10 weeks since Ramos had last held her 2-year-old, Alexa. Ten weeks since she was arrested crossing the border into Texas and U.S. immigration authorities seized her daughter and told her she would never see the girl again.

What followed — one foster family’s initially successful attempt to win full custody of Alexa — reveals what could happen to some of the infants, children and teens taken from their families at the border under a Trump administration policy earlier this year. The “zero-tolerance” crackdown ended in June, but hundreds of children remain in detention, shelters or foster care and U.S. officials say more than 200 are not eligible for reunification or release.

Federal officials insist they are reuniting families and will continue to do so. But an Associated Press investigation drawing on hundreds of court documents, immigration records and interviews in the U.S. and Central America identified holes in the system that allow state court judges to grant custody of migrant children to American families — without notifying their parents.