When Elizabeth Holmes goes on trial this fall, the patients who received erroneous test results from her company Theranos will be allowed to testify — a potentially critical piece of the case prosecutors will present to prove that her promises of using just a drop of blood to make medical diagnoses were actually fraud.

In an order filed Wednesday, US District Judge Edward J. Davila denied a motion by Holmes to suppress evidence of customer complaints and their test results in her criminal wire fraud trial. The ruling permits prosecutors to put patients on the witness stand as they attempt to prove that the 37-year-old former Silicon Valley CEO knew her company’s technology was likely to produce inaccurate results but promoted it anyway.

Attorneys for Holmes had argued that allowing prosecutors to use patient testimony, which they say is anecdotal, as evidence would violate her rights to due process. They said a company database that housed millions of test results and quality control data could have shown the technology produced accurate results, but it was lost as Theranos dissolved in the wake of Holmes’ indictment in 2018. A copy was provided to prosecutors, but investigators were never able to use it because they weren’t provided the encryption key needed to access its contents. Theranos dismantled the original database shortly after sending the copy to prosecutors.

Holmes’ attorneys blamed prosecutors for the “failure” to preserve access to the database that they said could have shown accurate test results, but the judge disagreed.

“It could just as likely contain incriminating evidence to the contrary,” Davila wrote. “Any exculpatory value is therefore speculative in nature.”

Representatives for Holmes’ defense team did not respond to BuzzFeed News’ request for comment. The US attorney’s office declined to comment.

Under a superseding indictment filed last year, Holmes and Theranos’s former president and chief operating officer, Ramesh “Sunny” Balwani, each face two counts of conspiracy to commit wire fraud — against investors and patients — and 10 counts of wire fraud.

Both Holmes and Balwani, who is facing a separate trial next year, have pleaded not guilty.

Holmes’ trial has been delayed multiple times due to the coronavirus pandemic and again this year after she told the court she was pregnant and due to give birth in July. Jury selection is currently scheduled to begin Aug. 31 with the trial likely beginning the following week.

Holmes had sought to revolutionize medicine with Theranos’s proprietary machine, which she claimed could run hundreds of blood tests on just a few drops of blood. The machine was supposedly faster, cheaper, and more accurate than all other blood-testing lab equipment on the market. Holmes’ claims drew prominent investors and glowing write-ups in magazines like Fortune and Forbes, but her story — and ultimately, her company — crumbled following a 2015 Wall Street Journal investigation.

In March 2018, the Securities and Exchange Commission charged Theranos, Holmes, and Balwani with “massive fraud,” alleging that they raised more than $700 million from 2013 to 2015 through an “elaborate, years-long” series of lies and exaggerations about the company’s business, finances, and technology. Holmes agreed to pay a $500,000 penalty to the SEC to settle the civil charges. Several months later, the Department of Justice indicted her and Balwani for wire fraud.

Prosecutors allege that the executives knew their blood tests produced unreliable results yet still sold them, and then committed wire fraud by electronically wiring those results to patients and doctors across state lines.

Several patients who were included on the prosecution’s list of potential witnesses for Holmes’ trial recently recounted their experiences to the Journal. One woman told the newspaper she received a test result that wrongly indicated that she was having a miscarriage. Another said he got a result that inaccurately suggested he could have prostate cancer.

The jury won’t hear about any physical or emotional harm they may have suffered as a result of the erroneous tests due to an earlier ruling by the judge limiting patients’ testimony to the facts. But the inclusion of patient testimony alone will likely be key to the prosecution’s case.

In court documents filed last year, prosecutors argued that their testimony “will greatly assist the jury in making their findings about the falsity of Defendant’s statements, her knowledge of their falsity, and her intent to defraud patients in general.”