The jury weighing fraud charges against former Theranos CEO Elizabeth Holmes conducted a fourth day of deliberations Monday without reaching a verdict. Holmes is facing 11 criminal charges alleging that she duped investors and patients by hailing her company’s blood-testing technology as a medical breakthrough when in fact it was prone to wild errors.

The eight men and four women on the jury have been meeting in a San Jose, California, federal courthouse after absorbing reams of evidence during a high-profile trial that has captivated Silicon Valley.

Last week, the jurors sent out two notes to U.S. District Judge Edward Davila — one making a swiftly rejected request to take their instructions home with them for further study and another that that allowed them a replay of a 2013 recording of Holmes discussing Theranos’ dealings with prospective investors.

The jury completed Monday’s session without providing any clues as to how far along it is in its deliberations. Jurors are scheduled to resume their discussion Tuesday morning.

The case has attracted worldwide attention. At its core is the rise and fall of Holmes, who started Theranos as a 19-year-old college dropout and then went on to break through Silicon Valley’s male-dominated culture with her bold claims and fundraising savvy. She become a billionaire on paper before it all evaporated amid allegations she was more of a charlatan than an entrepreneur.

Holmes, now 37, spent seven days on the witness stand acknowledging she made some mistakes and decisions she regretted while staunchly maintaining that she never stopped believing Theranos was on the verge of revolutionizing health care.

Holmes spent years promising Theranos would be able to scan for hundreds of diseases and other health problems with just a few drops of blood taken with a finger prick instead of relying on vials of blood drawn from a vein.

It was such a compelling concept that Theranos raised more than $900 million and struck partnerships with major retailers Walgreens and Safeway. Holmes herself became the subject of cover stories on business magazines.

But unknown to most people outside Theranos, the company’s blood-testing technology was flawed, often producing inaccurate results that could have endangered the lives of patients.

After the flaws were exposed in 2015 and 2016, Theranos eventually collapsed and the Justice Department filed a criminal case in 2018 that charged Holmes with 11 felony counts of fraud and conspiracy.

If convicted, Holmes could face up to 20 years in federal prison.