The California judge overseeing the criminal fraud case against the founder and CEO of defunct blood-testing company Theranos appeared skeptical the government is at fault for failing to preserve a test result database that her counsel claims is “the most important evidence in the case.”

In a virtual hearing Wednesday, Elizabeth Holmes’ attorneys at Williams & Connolly argued the government’s failure to preserve access to Theranos’ Laboratory Information System database, or LIS, denies the former biotech executive of critical evidence that could invalidate the government’s witness testimony claiming the tests were inaccurate and unreliable.