Thousands of US combat troops have started pulling out of Iraq, but hundreds of private security firms look set to fill the void. Since the US-led invasion in 2003, security contractors in Iraq have often been accused of operating above the law. Most controversially, In 2007, guards from what was then known as Blackwater Worldwide shot and killed 14 Iraqi civilians. These charges were dismissed in a US court. But as the US begins its year long withdrawal from Iraq, the message from the state department has been clear - more security contractors will be moved in to replace the US military. This, they say, is the most practical way to "fill the security gap" left by the departing American troops. There have been promises that contractors will not enjoy immunity from prosecution and will be governed by the laws of Iraq, but is this enough to quell concerns about the continuing presence of the security firms?