So there's nowhere to go to find out who was separated or not. And really, what happened was that there was no system in place for documenting separations. Sharyn Alfonsi: How do you separate a child from their parents, and there's no documentation?

It's very hard to know because there's no record. Michelle Brane: We estimate that over 1,000, somewhere between 1,000, 1,500 maybe more remain separated. Four federal agencies are working on it, but despite their power and reach, in seven months, they've only reunited 52 families. Michelle Brane leads the family reunification task force formed by President Biden in the first weeks of his presidency. They- in many cases, these children are with sponsors who they now call mommy and daddy, right? And so it's not as simple as just saying, "Gonna put you on a plane, and reunify you, and then we're done." So they're no longer at the addresses we may have last had for them.

Michelle Brane: It's been three-plus years for a lot of these families.