WASHINGTON AP – A multibillion-dollar pyramid scheme allegedly spawned by disgraced investor Bernard Madoff is being probed by a Senate panel that will, for the first time, question federal regulators responsible for inspecting investment firms and enforcing action against violations.

The Securities and Exchange Commission has faced heavy criticism over its failure to discover the $50 billion Ponzi scheme allegedly run by Madoff, the prominent Wall Street figure and money manager now fallen into disgrace – despite credible allegations against him that were brought to the agency over the course of a decade. Against the backdrop of the worst financial crisis since the 1930s, the SEC also is accused of contributing to that disaster with lax oversight of Wall Street and the markets, and lawmakers of both parties are calling for a shake-up of the agency to help restore investor confidence.