U.N. human rights experts are asking Washington to investigate a suspected Saudi hack that may have siphoned data from the personal smartphone of Jeff Bezos, Amazon founder and owner of The Washington Post. But the forensic evidence they cite comes from an incomplete study of Bezos’s phone, raising multiple questions. As a result, the findings that tie the hack to a WhatsApp account used by Crown Prince Mohammed bin Salman aren’t conclusive. That has some security experts puzzled. The forensics report comes from FTI Consulting, where it was overseen by a former FBI agent and White House cybersecurity official. FTI declined comment.