A body was reportedly found Saturday in a ship channel, north of the Long Island Village Community in Port Isabel.
Authorities said U.S. Customs and Border Protection picked up the body and notified the U.S. Coast Guard.
Local CBP officials and the U.S. Coast Guard are not releasing any more information.
Action 4 News was told if foul play was suspected, the Cameron County Sheriff's Office would be notified.
Sheriff Omar Lucio said he has not received a report about the body.
CBP spokesman Eddie Perez said any more information would come from the U.S. Customs and Border Protection Office of Air and Marine in Washington D.C.
Their office does not open until Monday morning.