June 25 (UPI) — A migrant boy who was held after crossing the U.S.-Mexico border literally walked away from the detention center in southeast Texas, authorities said — raising new questions about who is responsible for unaccompanied minors.

Officials said the unidentified 15-year-old boy left the Casa Padre child care facility in Brownsville, Texas, Saturday. The facility, a former Walmart store, has come under scrutiny since it was learned that migrant children separated from their parents were housed there.

The boy’s exit came as company officials try to assure federal lawmakers and news media who have toured the facility that migrant youths there are monitored and well cared for.

The facility, which opened last year, houses about 1,500 boys between the ages of 10 and 17.

Authorities have spoken to a man in Dallas who said he’s the child’s father. While authorities were trying to determine the relationship, the teen walked away from the facility.

Brownsville police launched a search that included a nearby pond but have not found the boy.

“As a licensed child care center, if a child attempts to leave any of our facilities, we cannot restrain them,” Jeff Eller, a spokesman for the company that runs the facility, said. “We are not a detention center. We talk to them and try to get them to stay. If they leave the property, we call law enforcement.

“It’s a conversation, a conversation that we’re here to help you, we’re here to help you get back

with your family. We can’t help you if you decide to leave.”

The incident has raised questions about the safety of underage, unaccompanied migrants detained under the Department of Justice’s “zero tolerance” program.

“If children are running away, that raises questions about the care that’s being provided,” said Michelle Brane of the non-profit Women’s Refugee Commission.

Some reports said the runaway teenager is headed back to Honduras through Mexico.

Last week, President Donald Trump signed an executive order to keep migrant children with their parents at detention facilities at the border. Over the weekend, he said some migrants who cross the border illegally should be sent back immediately.

The city of La Joya, just west of McAllen, announced last week it would no longer hold detainees at a facility there.

“Why should the city of La Joya, or any city in the Valley, detain any ICE illegals when ICE already has cages for them?” Mayor Jose “Fito” Salinas said Sunday.

“We’re totally against what they’re doing; I think we should unite the families, not divide them.”