In February 2010 23 Afghans travelling in three vehicles in Uruzgan province were attacked and killed by US helicopters firing Hellfire missiles and aerial rockets. A commander on the ground engaged in an operation thought the civilians were insurgents attempting to execute a flanking manoeuvre on his soldiers.
The investigation into the event, in which women and children were also injured, has now been published and blames "inaccurate and unprofessional reporting of the Predator crew" that was controlling the drone circling overhead at the time and was based thousands of miles away at Creech airforce base in Nevada, as well as "poorly functioning command posts" in Afghanistan.
The full report, totalling 2,100 pages, can be found here. A shocking interview with a female Afghan survivor in hospital can be found here.