WASHINGTON (Reuters) - Waste and fraud in US efforts to rebuild Afghanistan while fighting al Qaeda and the Taliban may have cost taxpayers billions of dollars, a special investigator said on Monday. Arnold Fields, special inspector general for Afghanistan reconstruction, said the cost of US assistance funding diverted or squandered since 2002 could reach well into the millions, if not billions, of dollars. There are no controls in place sufficient enough to ensure taxpayers money is used for the (intended) purpose, said Fields, whose independent office was created in 2008 to energise oversight of what US auditors have described as a giant, poorly coordinated aid effort that has sunk some $56 billion into Afghanistan since 2002. Of that sum, some $29 billion has gone to building up Afghanistans nascent security forces, many of whose members cannot read and are just learning to shoot. Another $16 billion has gone to trying to develop this poor country, where life expectancy is just 45 years and only 28 percent of people are literate, and to strengthening governance, said Fields, a retired Marine Corps major general. Experts believe it will take years to build an effective government that can provide basic services in Afghanistan, where corruption and the lack of a functional justice system have driven many villagers into the arms of the Taliban. US reconstruction activities are a major component in an even bigger outside assistance effort involving dozens of donor countries and hundreds of aid groups large and small. Fields office, known as SIGAR, described in a report issued this fall a