Tax havens - why governments have no money for welfare

Why is it that for every dollar that comes out of Africa another ten dollars leave it under the table. How comes that tax exempt foundations, global corporations, trusts and rich individuals are able to evade taxation with the help of some places like Jersey Island, Cayman Islands etc.
This deceitfulness is robbing not only the third world of the tax money which they could need for humanitarian causes, to alleviate poverty, shelter the homeless and feed the poor.
John Christensen a development economist explains how the fraud works and why the financial elite are in fact untouchable nor detectable.