Guardian investigation shows how US presidency blurs line between policy and enrichment of American ruling family and those around it On a graffitied Sarajevo backstreet, a path leads past an overgrown patch of garden to a white door. Beyond is the registered office of a company that is on the brink of winning contracts worth more than $1bn. AAFS Infrastructure and Energy is close to securing a concession to build and operate a pipeline across the Balkans to allow fossil gas shipped from the US