Fallen Silicon Valley star Elizabeth Holmes took the witness stand late Friday in her trial for criminal fraud. It was a surprise move by the ex-CEO of Theranos and her defense team after federal prosecutors concluded their case. Subscribe to KTVU's YouTube channel: / @ktvufox2 KTVU delivers the best in-depth reports, interviews and breaking news coverage in the San Francisco Bay Area and California Watch KTVU's newscasts on https://www.ktvu.com/live Download KTVU's news and weather apps for free at https://www.ktvu.com/mobile-apps Subscribe to KTVU's newsletter at https://www.ktvu.com/newsletters Follow KTVU on Facebook: / ktvu Follow KTVU on Twitter: / ktvu Follow KTVU on Instagram: / ktvu2