Some senior officials who have taken the test have been asked whether they said anything negative about the F.B.I. director, Kash Patel, in a highly unusual use of the tool.Typically, the F.B.I. has turned to polygraph tests to sniff out employees who might have betrayed their country or shown they cannot be trusted with secrets. Since Kash Patel took office as the director of the F.B.I., the bureau has significantly stepped up the use of the lie-detector test, at times subjecting personnel to a question as specific as whether they have cast aspersions on Mr. Patel himself. In interviews and...