Imagine you recently emigrated to America. The phone rings: Your child has crossed the border safely, the caller says. You can be reunited but have to pay "processing costs." No price is too great.

But this is all a twisted scam. The FBI warns that fraudsters are accessing the names of children who have crossed the border alone and are being held in federal facilities, and then digging up contact information on their families.

The FBI's San Antonio office says families in 12 states have been contacted. It hasn't released information about how many people have been scammed and how much money has been lost, and it is still tracking down who is responsible.

The Federal Trade Commission is warning that the callers often speak Spanish, claim to be social workers or government employees and know details about the children and their location. They ask families to send them money and require payments to be made through a bank account, money order or wire transfer.