Jury selection for the Elizabeth Holmes trial starts today.

Jury selection begins on Tuesday in the long-awaited trial of Elizabeth Holmes, the disgraced founder of the blood testing start-up Theranos who faces a dozen counts of fraud and conspiracy to commit wire fraud.

At the heart of the trial are questions of what exactly Ms. Holmes, 37, knew of the problems with Theranos’s blood-testing devices and whether she intentionally misled investors over the company’s technology. If convicted, she could serve up to 20 years in prison.

The case has captured public attention as another example of a Silicon Valley start-up gone wrong. But Theranos was unusual in that it was led by a female entrepreneur. Ms. Holmes exploited that difference, using it to build attention. She often wore a Steve Jobs-esque uniform of a black turtleneck and spoke in an unusually deep voice. Before Theranos fell from grace, Ms. Holmes was crowned the world’s youngest billionaire and regularly posed for magazine covers.

Her high profile may pose a challenge for jury selection. Prosecutors and her defense lawyers may find it difficult to pick jurors who have not already made up their minds about the case. Around half of the 200 potential jurors had already consumed media related to the case, according to court filings last week.

Potential jurors have filled out a 28-page questionnaire asking them about their media consumption habits, medical history and knowledge of more than 200 possible witnesses. An even more extensive questionnaire put forth by Ms. Holmes’s legal team included more than 100 questions. In June, it was rejected by Judge Edward Davila of U.S. District Court for the Northern District of California, who is overseeing the case. The trial is in San Jose, Calif.

Jury selection is expected to extend into Wednesday and could run longer. Opening arguments start next week.