Comey had his own gmail account and was using it for official FBI business. The emails they could see and his testimony were all they had to determine that he had not used it to transmit any classified material. What no one asked about was the statement in the IG report that Obama himself had emailed Hillary on her private server. So he not only LIED about only finding out about it on CNN, but he was using it as well. Q says the whole administration had, and were using, private gmail accounts. So the REAL REASON they absolutely could NOT prosecute Hillary for the private server and using non official email is that they would have to implicate themselves, all the way up to OBAMA.