The journalist are correct. Piedras Negras in across the border of Laredo in the state of Coahuila. There is also a Piedras Negras near Eagle Pass, but in a different state.
The Piedras Negras across from Eagle Pass is in the state of Coahuila.
If there is a Piedras Negras across from Laredo, it would be next to Nuevo Laredo -- and in the state of Tamaulipas.