She promised high returns but instead caused high anxiety for hundreds of investors who were scammed out of millions of dollars.

U.S. postal inspectors say they caught Kalin Dao with undercover video.  She is the mastermind behind the investment scheme that cost more than 500 victims at least $7 million.

Inspectors invested in Dao's company to learn about her business.

“She gladly took my money, sent me regular updates, investment statements categorizing how my investment was doing,” said US Postal Inspector, Robert Strande.

Those documents were all fake.  Strande traveled to Las Vegas to attend an investors meeting with Dao and brought a hidden camera.  He spoke with her about the transparency of her records.

Strande: “As far as reviewing the books, how, where are you located as far as doing that or sitting down and having a one on one meeting.”

Kalin: “Yeah, we, we can have one on one meeting. That no problem. But, it have to be member.”

Strande: “OK.”

Kalin: “You’re not a member right now. Ah, I can’t disclose that information to you.”

Strande: “Okay. Well, that’s what I don’t quite understand as far as bringing on new investors, but, you’re not disclosing a lot of information to the new investors.”

Kalin: “We not bringing on new investor. That what we trying to tell you.”

Strande: “But, I mean, if you were, I mean, how, how do you source of investors if you’re not putting out information?”

Strande says there's an important takeaway here for every potential investor.

“Don't accept answers like this is a private company, you're not entitled to look at the financials, I don't have to show you the financial records. Don't accept answers like that," he said.

Strande also says another potential red flag was the presentation Dao gave, specifically a chart that was used.

“She provided a Power Point presentation to the entire investment group and it looked as though a 2nd grader had done the art work,” he explained.

Strande says the victims were devastated, "“It completely wiped them out financially. Most of them did not have disposable income.”

Postal Inspectors say Dao used the money to finance her lavish gambling trips to Vegas.  She was sentenced to 12 years in prison.