Police in a number of cities are using drones to carry out airborne surveillance of protesters and rioters. Some of the high-tech machines are equipped with cameras and devices that can track cell signals. GOP Congressman Will Hurd of the San Antonio area, who is a former CIA agent, says surveillance of this nature is legal. State police used the drones in Houston last week to keep an eye on protest marches. The DPS says that the drones were used to protect the community and assist local police.