Politifact gets opinions on the FBI’s Clinton investigation from several experienced former officials who have no specific inside knowledge of the case.
Ellen Glasser, a retired FBI official who worked on mishandled classified information cases, says, “We don’t do these [investigations] because we’re curious. There’s a potential that a criminal violation took place. […] My experience tells me that Hillary Clinton is a subject of a criminal investigation.”
Mark Pollitt, former head of the FBI’s computer forensics program, says, “You don’t know if it’s criminal until you get to the end of it.” Noting that the investigation has lasted for at least nine months, he adds, “If this thing was dead on arrival, nobody would be willing to keep this thing going.”
However, it is still unknown if Clinton is a subject or target of the investigation. A “target” is someone who prosecutors believe is linked to a crime by substantial evidence. It is common practice for prosecutors to tell people if they are targets if they ask. However, it doesn’t appear that Clinton has asked. She has claimed that she has had no contact with the FBI about the investigation so far. (Politifact, 5/12/2016)