I checked the Zapruder... It does appear to me that Kellerman has the mic before the headshot...
Oh really?
Altgens 6 is inconclusive which hand is on the mic/radio. Although it does show Kellerman to be at the far right of the limo (staring into the side mirror). He hasn't moved over towards the limo mic which is next to Greer's steering wheel.
Possibly Greer changes the mic from the right hand to his left hand. below
Which then gives you Greer holding the mic in his left hand
I don't think it was ever answered if there are two mics in the limo
on that dayGreer told FBI agents Sibert & O'Neill on the night of the autopsy, during an ''informal interview''.
Greer stated that he first heard what he thought was
possibly a motorcycle backfire and glanced around and noticed
that the President had evidentlv been hit. He thereafter qot
on the radio and communicated with the other vehicles, stating
that they desired to get the President to the hospital immediately.
Greer denied making those comments to FBI agents Sibert & O'Neill when question by Arlen Specter. Greer stated only Kellerman used the limo mic! from 'Testimony of William Robert Greer, Special Agent, U.S. Secret Service, March 9, 1964, -214a131:'
Greer covering Kellerman's ass, or worse?