We will know the matter is close to completion when HUma and Hilary are called back to the FBI to supplement their original testimony.
They have already narrowed the field considerably....they found emails which should not have been on the computer which triggered the new situation.
Think about how Comey went out of his way to make Clinton look bad earlier this year without coming out and saying anything specific. The issue now is folks outside the FBI have this stuff, they know exactly what is there and it is bad enough for Comey to have a come to Jesus moment.
The veil has been torn.
Every outrageous thing Trump has said has come to fruition. “you would be in jail” will be the next.