SAN FRANCISCO — A grand jury has indicted CEO Elizabeth Holmes and her former No. 2 Sunny Balwani for alleged fraud at Theranos, the disgraced Silicon Valley company that once promised to revolutionize blood testing in a pitch that was too good to be true.

The criminal charges filed by federal prosecutors allege that Holmes and Balwani bilked investors out of hundreds of millions of dollars while also defrauding doctors and patients through years of lies that put thousands of people in personal danger.