(CNN) Some immigrant children have arrived to refugee resettlement care with their parents' contact information hastily written on their clothes.

In one case, a child came holding his father's belt, which had a name and phone number written inside it. In other cases, the parents have taught the children a rhyme to remember contact information.

Dona Abbott, Grand Rapids, Michigan, branch director of refugee services for Bethany Christian Services, described a resettlement process thrust into turmoil amid the Trump administration's zero-tolerance policy toward undocumented immigrants.

In some instances, case workers are given no information about the identity of the children's parents or family.

"The case manager tries to identify who the parents are," Abbott said. "What we do is call the detention centers in the state where the child entered across the border and start asking if the parent is there."

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