No, they claim no evidence of intent, which is key for proving criminality. Gross negligence is an impossible prosecution where a defendant at a jury trial is a 68 yr old grandmother and the central issue is an email server. The upside here - if there is any - is that now Comey has all the credibility he needs to investigate the Clinton Foundation.
The defendant is not a 68 year old grandmother, the defendant is a former secretary of state with a staff of "experts", and everyone knew better. Ignorance is not a defense in any court of law.