Theranos deputy's fraud trial opens in Silicon Valley

A top aide and ex-boyfriend of fallen Theranos founder Elizabeth Holmes went on trial Tuesday in California, with prosecutors arguing Ramesh "Sunny" Balwani was equally responsible for the massive fraud at the startup.

Holmes was convicted last year of defrauding investors in the blood testing company once hailed as revolutionary and valued in the billions of dollars, but which collapsed under claims its technology did not work as promised.

US prosecutor Robert Leach told jurors in a federal courthouse in San Jose, the heart of Silicon Valley, that the pair shared responsibility for the firm's operations.

"The evidence will show that they ran the company together. You will see how they were partners in everything, including their crime," Leach said in his opening arguments.

"Balwani had no medical degree, no experience building medical devices. What he did have was a connection to Elizabeth Holmes. Mr Balwani was her romantic partner," he added.

Balwani, nearly two decades Holmes's senior, was brought in to help run the company she had founded in 2003 at age 19. He has pleaded not guilty.

Holmes, now 38, would eventually promise self-service testing machines that could run an analytical gamut cheaply and on just a few drops of blood -- a pledge shattered under fraud allegations.

Prosecutors alleged she knew the technology did not work as advertised, but continued to promote it as revolutionary to patients and the investors who poured money into the company.

As Theranos soared, it attracted luminaries such as Rupert Murdoch and Henry Kissinger, but a series of reports casting doubt on the firm's claims from Murdoch's own Wall Street Journal set the company's collapse in motion.

The paper's series of stories raising questions about the much-hyped technology heralded the beginning of the end for Theranos.

Holmes was convicted in January after a high-profile trial, and now faces the possibility of a prison term when she is sentenced at a hearing set for September.