Education Secretary Betsy DeVos's family has reportedly lost tens of millions of dollars from their investment in embattled medical-testing startup Theranos, according to newly unsealed documents.

DeVos's family was among a list of prominent figures who lost a total of $600 million in investments in the blood-testing company now facing federal fraud charges, The Wall Street Journal reports.

The Education secretary's family invested $100 million in the company, according to the Journal, a figure not previously reported.

The list of investors who poured millions into Theranos between 2013 and 2015 was made public after documents were unsealed Thursday in a lawsuit against the company.

A spokesman for the holding company used by DeVos and her husband said it was an "understatement" to say the family was "disappointed" by the failure of Theranos.

Other big-time investors whose net-worths took a hit from the backfire are the family of Walmart founder Sam Walton ($150 million), conservative media mogul and 21st Century Fox Executive Chairman Rupert Murdoch ($125 million) and Mexican newspaper investor Carlos Slim ($30 million), the Journal reported.

According to the newspaper, Theranos founder Elizabeth Holmes warned investors in an April 10 email that the company would soon be liquidated.

Theranos claimed, and "investors believed," it had developed revolutionary technology that could conduct a wide variety of blood tests from just a small sample, according to documents outlying the charges against the company.

The company has been charged with "massive fraud" by the Securities and Exchange Commission (SEC) and is currently under federal investigation for its statements used to lure investors.

Holmes has agreed to settle the fraud charges against her and her company by giving back some of her Theranos stock, giving up voting control of the company and paying a $500,000 penaly.