Even some of the world’s richest people may get duped, according to newly unsealed documents in a lawsuit filed on behalf of investors in the failing blood-testing company Theranos.

High-profile investors who collectively lost hundreds of millions of dollars included Walmart’s Walton family, the media mogul Rupert Murdoch, as well as Betsy DeVos, the secretary of education and her relatives.

The list of investors, which was first reported by The Wall Street Journal, came to light as part of a class-action lawsuit brought in 2016 by Robert Colman, a retired Silicon Valley investment banker, who claims that Theranos misled investors about its business and technology.

Theranos, founded by Elizabeth Holmes when she was a 19-year-old Stanford University dropout, promised to revolutionize the lab industry using a few drops of blood from a simple finger-prick to look for everything from diabetes to cancer, at a fraction of the cost of a traditional blood test.

The company became a Silicon Valley fairy tale, with investors awarding the privately held company a valuation of around $9 billion. But the story began to unravel in October 2015 after The Wall Street Journal, owned by Mr. Murdoch’s News Corp., began questioning whether the tests worked. Theranos became the subject of federal investigations into its testing and claims of proprietary technology, which were called “nanotainers.” Much of the time the company had to resort to using conventional blood testing methods, unable to get federal approval for any test but one for Herpes.

Theranos and its founder also became embroiled in a series of lawsuits, involving investors as well as one of its key partners, Walgreens, a large drugstore chain, where it offered its tests. The company reached a settlement with Walgreens last August.

In March, the Securities and Exchange Commission charged Ms. Holmes with fraud, accusing her of exaggerating and lying about her technology to attract investors. As part of the S.E.C. action, Ms. Holmes agreed to pay $500,000, give up control of her company, and is barred from serving as an officer or director of any public company for 10 years. She and Theranos did not admit nor deny the allegations.

Theranos still faces the class-action lawsuit, and may still be subject to a criminal investigation by the United States attorney in San Francisco. The company’s future is unclear. The company did not respond to requests for comment.

Theranos had always boasted a star-studded list of investors and directors — its board included the former secretaries of state George P. Shultz and Henry A. Kissinger, two former United States senators, and Gen. Jim Mattis, the current secretary of defense. But while some high-profile investors’ links to Theranos had been previously known, the new documents provide a detailed list of financial amounts.

The Walton family invested about $150 million in 2014 through two separate entities, according to the investor list. Mr. Murdoch put in about $125 million, and the extended family of Ms. DeVos invested about $100 million.

“It’s obvious that they are highly disappointed in them as a company and as an investment,” said Greg McNeilly, the chief operating officer of The Windquest Group, the holding company of Ms. DeVos and her husband. Mr. McNeilly said the $100 million was a joint investment across multiple generations and branches of her family, and described the share held by Ms. DeVos and her husband as “minor.”

Other prominent investors, according to the list, included the Cox family; the Atlanta billionaires who own the media conglomerate Cox Enterprises and who invested $100 million; and a company affiliated with Mexican billionaire Carlos Slim that put in about $30 million. Robert K. Kraft, the owner of the New England Patriots, invested $1 million.

Representatives for Mr. Kraft, the Walton family, Cox Enterprises and News Corp. declined to comment.