Elizabeth Holmes Warns Lab Chief’s Testimony May Upend Trial

Of all the high-profile witnesses set for Elizabeth Holmes’s criminal trial, Kingshuk Das isn’t exactly a key player in the collapse of Theranos Inc. But Das poses enough of a risk for her defense that her lawyer said his testimony threatens to upend the proceeding.

Das, a former lab director for Theranos, has said he told Holmes, who founded the company and was its chief executive officer, that its blood-testing equipment was deficient and not reliable, court filings show. He’s one of the few high-level scientists positioned to explain to jurors how aware Holmes was of problems with the ...