The FBI is investigating how and why classified information ended up on Clinton’s server. The probe probably will take at least several more months, according to the person, who described the matter on condition of anonymity because the investigation is continuing and deals with sensitive information.

A review by Clinton and her aides determined that about half of the 60,000 e-mails she exchanged during her four-year tenure as secretary of state were of a personal nature, the presidential candidate has said.