Saying he feared for his safety at times during his decade-long effort to expose Bernard Madoff’s alleged Ponzi scheme, whistleblower Harry Markopolos testified Wednesday for the first time at a Congressional hearing.

Often bristling with anger, Markopolos excoriated the Securities and Exchange Commission for ignoring his repeated calls for a government investigation into Madoff’s investment advisory firm.

“My team and I tried our best to get the SEC to shut down Madoff,” said Markopolos. “A fraud that should have been stopped at under $7 billion in 2000 has grown to over $50 billion.”

Markolopos, a Boston-based securities industry investigator, urged the creation of a single whistle-blower office to oversee all allegations of fraud in the securities industry.

 “The SEC is overmatched,” he observed at one point during his 90-minute testimony.

In response to a question regarding other possible Ponzi schemes still operating, Markopolos said he will turn over evidence of a $1 billion fraud to the SEC at a meeting on Thursday.

Markopolos said he used public information – primarily marketing material Madoff sent to potential investors – to conduct his investigation and build a case against the now-disgraced financier.

He said it took him “five minutes” to determine Madoff’s operations were a fraud.

Madoff was arrested on Dec. 11 and, according to court documents, has admitted to FBI investigators that his investment business was a “giant Ponzi scheme.”

Investors of all stripes were drawn in, including wealthy European families, Hollywood celebrities, numerous charitable organizations and a handful of universities.

Investigators say it might be the largest Ponzi scheme ever.

Markopolos said the SEC lacks the expertise to detect fraud in the trading of the myriad complex financial products that 

have emerged in recent decades.

In addition, turf wars between the regional branches of the SEC in New York and Boston prevented the necessary communication and cooperation that might have brought down Madoff earlier, he said.

Moreover, Markopolos said the SEC – as well as other financial industries regulatory bodies, notably the Financial Industry Regulatory Authority -- operate at the mercy of the big Wall Street banks and the powerful men who run those banks.

“Mr. Madoff was one of the most powerful men on Wall Street,” he said. “Clearly the SEC was afraid of Mr. Madoff.”

“You’ve basically said two of our largest regulators see their role as protecting the major institutions rather than protecting investors,” said Congressman Brad Sherman, D-Calif.

Markopolos didn’t disagree.

The likelihood of getting caught is so remote and the rewards so vast that criminals believe it’s well worth the risk of breaking the law, Markopolos noted.

In a statement obtained by Fox Business Network on Tuesday prior to Markopolos’ testimony before the House subcommittee, the whistleblower said he began his investigation into Madoff in late 1999 when a marketing executive from Rampart Investment Management Company Inc. told him of Bernard Madoff’s fantastic returns.

According to the statement: Markopolos contacted the SEC’s Boston office in May 2000 with his findings. The next year, Madoff spoke with Ed Manion in that office.

“Throughout the past 9 years, Ed Manion was the only SEC staff member who ever truly understood the Madoff scheme and the threat it posed to the public,” Markopolos stated.

Manion told Markopolos to send the information to the SEC’s New York Regional Office, which he did in 2001. Markopolos said his report, “Madoff Investment Process Explained,” received no response.

The following year, Markopolos said he flew to Europe on a business trip, where he spoke with 14 French and Swiss private client banks who bragged about Madoff, his returns and their “special access to him.”

Markopolos said it was there he realized Madoff was running a Ponzi scheme.

Madoff's “masterful use of ‘hook’ by playing hard to get and his false lure of exclusivity were symptomatic of a Ponzi scheme. The dead give-away was the need for new money,” said the statement. “I also came to realize several European Royal families were invested.”

Markopolos finally met with the SEC’s Boston Regional Office Branch Chief, Mike Garrity in October 2005. 

Markopolos said Garrity was “interested and fully engaged.”

“He told me that if [Madoff] were located within the New England region, he would have had an inspection team inside [his] operation the very next day,” Markopolos stated.

At that point, Markopolos said Garrity tagged him the “Boston Whistleblower” to protect Markopolos’ identity.

Later that year, Markopolos said he submitted to the SEC a report titled “The World’s Largest Hedge Fund is a Fraud,” which raised 28 red flags.

Markopolos said Garrity referred Markopolos to New York Branch Chief Meaghan Cheung, who according to Markopolos, wasn’t interested.

In an e-mail Markopolos said he sent to Cheung in 2007, the whistleblower wrote, “when Madoff finally does blow up, it’s going to be spectacular, and lead to a massive selling by hedge fund, fund of funds as they face investor redemptions.”

Cheung, in an interview with the New York Post, said, “Why are you taking a mid-level staff person and making me responsible for the failure of the American economy? I worked very hard for 10 years to make a career, and a reputation, and that has been destroyed in a month.”

Markopolos said he continued that year and the next, finally sending his updated 2005 report to the SEC in 2008.

“I tried calling back a few times but never got through and gave up,” said Markopolos.

By December the alleged Ponzi scheme had surfaced.

“It is a sickening thought, but if the SEC had bothered to pick up the phone and spend even one hour contacting the leads, then [Madoff] could have been stopped in early 2006,” Markopolos said.

Markopolos submitted to the Congressional subcommittee nearly 400 pages of testimony, documents, emails, letters, faxes, charts and graphs. He praised the efforts of three other investigators who helped him with the investigation.

 --Rich Edson contributed to this article.