18-year-old Michael Brown ... was fatally shot by officer Darren Wilson. The final few minutes of Brown's life had been captured by a small surveillance camera rolling inside a nearby grocery shop. As protesters have taken to the streets to demonstrate over Brown's death, even a year on, so a legion of amateur cameramen and women have begun watching officers closely, posting recordings that undermine the monopoly once held by police on the official version of events. The surge in vigilante recording is being met with aggressive resistance from police. Judges uphold the right of American people to film law enforcement officers under the first amendment of the US constitution. But officers increasingly complain that filming interferes with their duties. An increasing number are taking direct action to prevent recordings - snatching or smashing phones or demanding the handover of footage, sometimes even after it has been livestreamed directly online. For many who capture horrific acts of violence, returning to a normal life becomes impossible. They complain of harassment by police, of threats against their life and of recurring trauma as a result of the death and brutality they have witnessed. Carlos Miller [is] a former journalist who now tracks the issue on his website Photography Is Not A Crime. Already this year, the site has reported on 87 cases in which people were arrested, manhandled or threatened for filming police. The rate of such incidents has increased in recent years, Miller says.