Eighty-four undocumented migrants were “rescued” from a tractor-trailer just north of the Texas border with Mexico Thursday, Hidalgo County Sheriff Eddie Guerra said on Twitter.

“A concerned citizen called to report a tractor trailer arrive at a residence … and seeing people unloading from the trailer,” Guerra said, adding that authorities responded and “rescued 84 UDI’s (undocumented immigrants).”

The location Guerra specifies in his tweet is described by Google as “a Census-designated area” known as Olivarez.

He told CNN that ICE Homeland Security Investigations are probing the incident as a human smuggling case.

Guerra also told CNN the people on the 18-wheeler are from Central America and none at the scene asked for medical aid.