Lawyers have been unable to find the parents of 545 children separated at the Mexico boarder after the majority of families were deported back to Central America, according to the ACLU.
A court filing from the American Civil Liberties Union showed they have only made contact with parents of 550 children out of the 1,000 families separated at the border in 2017, according to NBC News.
While 25 of those parents may have a chance of returning for reunification, several families contacted by the federal court-appointed committee to identify separated families chose to leave their children in the US with a family member or sponsor.
Lee Gelernt, deputy director of the ACLU Immigrants' Rights Project, told NBC News that hundreds of families have still not been found.
"People ask when we will find all of these families and, sadly, I can’t give an answer. I just don’t know," Mr Gelernt said. "The tragic reality is that hundreds of parents were deported to Central America without their children, who remain here with foster families or distant relatives.”
Justice in Motion, the group on the ground in Mexico and Central America physically searching for the separated families, said in a statement they were continuing to look for more deported parents.
“It’s an arduous and time-consuming process on a good day. During the pandemic, our team of human rights defenders is taking special measures to protect their own security and safety, as well as that of the parents and their communities,” the statement shared with NBC said.
The Trump administration began trialling a "zero tolerance" policy at the US's southern border in a pilot programme in 2017.