Advocatus Diaboli writes: n a secret test of mass surveillance technology, the Los Angeles County Sheriff's Department sent a civilian aircraft* over Compton, California, capturing high-resolution video of everything that happened inside that 10-square-mile municipality. Compton residents weren't told about the spying, which happened in 2012. "We literally watched all of Compton during the times that we were flying, so we could zoom in anywhere within the city of Compton and follow cars and see people," Ross McNutt of Persistence Surveillance Systems told the Center for Investigative Reporting, which unearthed and did the first reporting on this important story. The technology he's trying to sell to police departments all over America can stay aloft for up to six hours. Like Google Earth, it enables police to zoom in on certain areas. And like TiVo, it permits them to rewind, so that they can look back and see what happened anywhere they weren't watching in real time.