The watchdog of the Securities and Exchange Commission has found that three agency exams and two investigations of Bernard Madoff's business were incompetent, despite ample warnings of the multibillion-dollar fraud.

But SEC inspector general David Kotz's report found no evidence of any improper ties between agency officials and Madoff.

Despite speculation that senior SEC officials may have tried to influence the probes, a summary of Kotz's report also found no evidence of that.

Revelations in December of the agency's failure to uncover Madoff's massive pyramid scheme over a decade touched off one of the most painful scandals in the agency's 75-year history.