DALLAS — The United States Postal Service continues to investigate hundreds of Christmas cards missing from its Park Cities-area branch, as News 8 gets new complaints from customers who say their mail was never delivered.

Tuesday, the US Postal Service said it was investigating personnel inside the branch. That’s changed.

Wednesday, they say they’re focused on the possibility that the mail was stolen from the drop-off box.

Postal Service investigating outside theft as cause of missing Park Cities mail