They aren’t sure if the analysis reveals two or three rifles. Their best guess is two shooters followed by the Counter Sniper shot.
There is fascinating acoustic analysis that shows shot echoes off a large flat wall for the first three shots, but no similar echoes for the next group of shots. He even postulates the lack of echo on the second group of shots was because the shooter was indoors.
He also examines the elevation of the shooter, the elevation of President Trump’s head, and the elevation of the wounded audience member. He concludes at least one bullet had to be fired with an upward slope, not downward from the building roof.
He’s assuming the ground is level and the buildings are on the same level as the stage and stands.
Bad logic.
If no echo could be heard, no SHOT could be heard either.
Indoors... BAH!