Some say that Bernard L. Madoff is the biggest financial fraud in history. The New York Times gives us some background on Mr. Madoff

"For Bernard L. Madoff, there was also his multimillion-dollar private foundation that doled out money to hospitals and theaters. Indeed, through his charity work at places like the Gift of Life Bone Marrow Foundation or his public service at institutions like Yeshiva University, where he served on the board, Mr. Madoff seemed to have created a stainless persona of integrity and trust. And that fit with his rate of return, which was never attention-grabbing, just solid 12-13 percent year in, year out."

How did Mr. Madoff keep his new investments at such a high rate of return and keep paying off investors and giving to charities? Explain how he was able to do what he did financially so long.