“There has to be something behind this to make that move.”
Speculation can be rampant, but first of all, It seems implausible that they are just now getting around to Carlos and his wife. So my bet is that they’ve had this stuff for some time now and have probably done a lot of internal investigating of the contents. Then why now? I think that Comey sees the handwriting on the wall that Trump is likely to win the election. Ergo, he has no cover, so he’s trying this at this late hour to try and keep himself out of jail. My two cents anyway!
Taken at face value, if they were examining Weiner's device (sheesh, you can't get away from the innuendo) and found emails from Huma with State Department business, then they have to be investigated. That is, of course, if there is a shred of honesty left in the FBI.