The placement and monitoring of a tracking device on the defendant's vehicle by U.S. Air Force personnel was not an unlawful search even though the placement was not authorized by a state district judge. There was no violation of the Posse Comitatus Act because the military is authorized to use military resources on civilians if there is an independent military purpose for their involvement. Also, the Air Force was authorized to track the defendant based on military rules and regulations because the defendant had access to the Air Force base. In addition, a state district judge did not have to authorize the tracking device because no Texas statute governs the use of tracking devices by federal agents. Finally, monitoring the defendant's vehicle did not violate the 4th Amendment because the rural ranch property in question falls squarely within the definition of "open fields" in which there is no expectation of privacy. Davidson v. State, 03-06-00717-CR [1].