How many whistleblowers does it take?

It seems that Harry Markopolos wasn't the only person blowing the whistle on the Ponzi scheme being run by money manager Bernard Madoff. News is now out that there were several people who contacted the Securities and Exchange Commission between 2003 and 2006 with complaints.

The reports to the SEC included questions about the unusually high and consistent trading returns and the relationship between Madoff and the feeder fund Fairfield Greenwich Group. It seems Markopolos wasn't the only person who thought the lack of any losses was unusual. One specific complaint to the SEC alleged that $10 billion belonging to a deceased investor had been co-mmingled (improperly combined with other money).

The SEC is 'fessing up to 12 complaints being lodged about Madoff. That makes me wonder how many more there were, both in writing and verbally. Surely this is only the tip of the iceberg, and I suspect that the more we investigate, the more the government agency will be exposed as negligent in responding to whistleblower reports.