Martha Raddatz?
That hit didn't kill Seth Rich tho. The resident at the hospital said to multiple sources that he was coherent and the injuries didn't appear to be life threatening. He was shocked to come back a few hours later and not allowed to see "the body". Seth Rich was either killed at the hospital .. or he is not dead.
The other thing to add into your list is the fact that the DC Mayor and Donna Brazile were at the hospital that night .. middle of the night. What were they doing there?