Hillary Clinton testified before Congress and in her time before the committee, was asked many questions with regards to her e-mails.  She answered many of them blatantly falsely, as evidenced by the testimony of FBI Director Comey.  Perjury is a serious crime, and non-Clinton citizens are arrested for it.  

She claimed that there were no e-mails sent or received on her illegal private e-mail server that were marked as classified in any way.  

The FBI director testified they found classified documents.

She had all the e-mails in her server subpoenaed and she destroyed 33,000 e-mails.  She proceeded to destroy the devices that contained the e-mail on a client side, some with hammers, and the server was wiped with BleachBit software to destroy any chance of recovering the data.  These acts are blatant failures to comply with the subpoena, and are clear and blatant obstruction of justice acts, and despite the failures of DOJ and FBI to pursue charges, they should be prosecuted properly.  These charges need to be filed before the next administration takes office because these are not political charges, but instead matter of law and if they are filed after the transition of power, then Clinton and her allies will claim it is political prosecution, not the matter of law that is really there.